<s>
Commander	B-Application
Keen	I-Application
is	O
a	O
series	O
of	O
side-scrolling	O
platform	O
video	O
games	O
developed	O
primarily	O
by	O
id	O
Software	O
.	O
</s>
<s>
The	O
series	O
consists	O
of	O
six	O
main	O
episodes	O
,	O
a	O
"	O
lost	O
"	O
episode	O
,	O
and	O
a	O
final	O
game	O
;	O
all	O
but	O
the	O
final	O
game	O
were	O
originally	O
released	O
for	O
MS-DOS	B-Application
in	O
1990	O
and	O
1991	O
,	O
while	O
the	O
2001	O
Commander	B-Application
Keen	I-Application
was	O
released	O
for	O
the	O
Game	B-Device
Boy	I-Device
Color	I-Device
.	O
</s>
<s>
The	O
series	O
follows	O
the	O
eponymous	O
Commander	B-Application
Keen	I-Application
,	O
the	O
secret	O
identity	O
of	O
the	O
eight-year-old	O
genius	O
Billy	B-Application
Blaze	I-Application
,	O
as	O
he	O
defends	O
the	O
Earth	O
and	O
the	O
galaxy	O
from	O
alien	O
threats	O
with	O
his	O
homemade	O
spaceship	O
,	O
rayguns	O
,	O
and	O
pogo	O
stick	O
.	O
</s>
<s>
The	O
first	O
three	O
episodes	O
were	O
developed	O
by	O
Ideas	O
from	O
the	O
Deep	O
,	O
the	O
precursor	O
to	O
id	O
,	O
and	O
published	O
by	O
Apogee	O
Software	O
as	O
the	O
shareware	B-License
title	O
Commander	B-Application
Keen	I-Application
in	I-Application
Invasion	I-Application
of	I-Application
the	I-Application
Vorticons	I-Application
;	O
the	O
"	O
lost	O
"	O
episode	O
3.5	O
Commander	B-Application
Keen	I-Application
in	I-Application
Keen	I-Application
Dreams	I-Application
was	O
developed	O
by	O
id	O
and	O
published	O
as	O
a	O
retail	O
title	O
by	O
Softdisk	O
;	O
episodes	O
four	O
and	O
five	O
were	O
released	O
by	O
Apogee	O
as	O
the	O
shareware	B-License
Commander	B-Application
Keen	I-Application
in	I-Application
Goodbye	I-Application
,	I-Application
Galaxy	I-Application
;	O
and	O
the	O
simultaneously	O
developed	O
episode	O
six	O
was	O
published	O
in	O
retail	O
by	O
FormGen	O
as	O
Commander	B-Application
Keen	I-Application
in	I-Application
Aliens	I-Application
Ate	I-Application
My	I-Application
Babysitter	I-Application
.	O
</s>
<s>
Ten	O
years	O
later	O
,	O
a	O
homage	O
and	O
sequel	O
to	O
the	O
series	O
was	O
developed	O
by	O
David	O
A	O
.	O
Palmer	O
Productions	O
and	O
published	O
by	O
Activision	O
as	O
Commander	B-Application
Keen	I-Application
.	O
</s>
<s>
Invasion	B-Application
of	I-Application
the	I-Application
Vorticons	I-Application
was	O
the	O
only	O
game	O
developed	O
by	O
Ideas	O
from	O
the	O
Deep	O
,	O
and	O
was	O
based	O
on	O
programmer	O
John	O
Carmack	O
's	O
creation	O
of	O
adaptive	O
tile	O
refresh	O
,	O
a	O
technique	O
that	O
allowed	O
IBM-compatible	O
general-purpose	O
computers	O
to	O
replicate	O
the	O
smooth	O
scrolling	O
of	O
video	B-Device
game	I-Device
consoles	I-Device
such	O
as	O
the	O
Nintendo	O
Entertainment	O
System	O
.	O
</s>
<s>
Their	O
obligations	O
to	O
Softdisk	O
,	O
where	O
they	O
had	O
worked	O
during	O
development	O
of	O
the	O
game	O
,	O
led	O
to	O
the	O
creation	O
of	O
Keen	B-Application
Dreams	I-Application
as	O
a	O
prototype	O
for	O
the	O
second	O
trilogy	O
of	O
episodes	O
.	O
</s>
<s>
The	O
final	O
episode	O
was	O
split	O
off	O
during	O
development	O
into	O
a	O
stand-alone	O
retail	O
title	O
,	O
and	O
plans	O
for	O
a	O
third	O
trilogy	O
were	O
cancelled	O
after	O
the	O
success	O
of	O
Wolfenstein	B-Application
3D	I-Application
(	O
1992	O
)	O
and	O
development	O
focus	O
on	O
3D	O
first-person	O
shooters	O
such	O
as	O
Doom	B-Application
(	O
1993	O
)	O
.	O
</s>
<s>
Critical	O
reception	O
and	O
the	O
series	O
 '	O
legacy	O
has	O
focused	O
on	O
the	O
two	O
main	O
trilogies	O
of	O
episodes	O
,	O
with	O
Vorticons	B-Application
having	O
large	O
success	O
as	O
a	O
shareware	B-License
game	O
and	O
impacting	O
the	O
success	O
of	O
Apogee	O
(	O
now	O
3D	O
Realms	O
)	O
and	O
its	O
shareware	B-License
model	O
.	O
</s>
<s>
The	O
MS-DOS	B-Application
games	O
have	O
been	O
re-released	O
in	O
several	O
compilation	O
packages	O
,	O
and	O
all	O
but	O
the	O
sixth	O
episode	O
are	O
still	O
sold	O
through	O
modern	O
emulation	O
releases	O
on	O
platforms	O
such	O
as	O
Steam	B-Application
.	O
</s>
<s>
Commander	B-Application
Keen	I-Application
in	I-Application
Invasion	I-Application
of	I-Application
the	I-Application
Vorticons	I-Application
is	O
the	O
first	O
game	O
in	O
the	O
series	O
,	O
released	O
on	O
December	O
14	O
,	O
1990	O
for	O
MS-DOS	B-Application
.	O
</s>
<s>
"	O
,	O
and	O
the	O
game	O
was	O
published	O
through	O
a	O
shareware	B-License
model	O
whereby	O
"	O
Marooned	O
on	O
Mars	O
"	O
was	O
released	O
for	O
free	O
,	O
and	O
the	O
other	O
two	O
episodes	O
were	O
available	O
for	O
purchase	O
.	O
</s>
<s>
Commander	B-Application
Keen	I-Application
in	I-Application
Keen	I-Application
Dreams	I-Application
is	O
the	O
second	O
game	O
of	O
the	O
series	O
,	O
released	O
in	O
1991	O
as	O
a	O
single	O
episode	O
;	O
it	O
is	O
sometimes	O
referred	O
to	O
as	O
episode	O
3.5	O
of	O
the	O
series	O
.	O
</s>
<s>
It	O
was	O
developed	O
for	O
MS-DOS	B-Application
by	O
id	O
Software	O
,	O
which	O
had	O
been	O
founded	O
by	O
the	O
Ideas	O
from	O
the	O
Deep	O
team	O
after	O
the	O
success	O
of	O
the	O
first	O
game	O
,	O
and	O
published	O
through	O
Softdisk	O
as	O
part	O
of	O
an	O
agreement	O
between	O
the	O
companies	O
as	O
the	O
founders	O
of	O
id	O
had	O
been	O
employees	O
of	O
Softdisk	O
when	O
they	O
developed	O
Vorticons	B-Application
.	O
</s>
<s>
In	O
2013	O
a	O
port	O
was	O
developed	O
by	O
Super	O
Fighter	O
Team	O
for	O
Android	B-Application
devices	O
,	O
and	O
a	O
2014	O
Indiegogo	O
crowdfunding	O
campaign	O
led	O
to	O
the	O
original	O
source	O
code	O
being	O
released	O
under	O
GNU	B-License
GPL-2.0-or-later	I-License
and	O
a	O
release	O
by	O
Hard	O
Disk	O
Publishing	O
through	O
Steam	B-Application
for	O
Microsoft	B-Application
Windows	I-Application
and	O
Linux	B-Application
in	O
2015	O
,	O
and	O
OS	B-Operating_System
X	I-Operating_System
in	O
2016	O
.	O
</s>
<s>
A	O
Nintendo	B-Application
Switch	I-Application
version	O
was	O
released	O
by	O
Lone	O
Wolf	O
Technology	O
in	O
2019	O
.	O
</s>
<s>
Commander	B-Application
Keen	I-Application
in	I-Application
Goodbye	I-Application
,	I-Application
Galaxy	I-Application
was	O
released	O
for	O
MS-DOS	B-Application
on	O
December	O
15	O
,	O
1991	O
as	O
the	O
second	O
main	O
game	O
in	O
the	O
series	O
.	O
</s>
<s>
Consisting	O
of	O
episodes	O
four	O
and	O
five	O
of	O
the	O
series	O
,	O
"	O
Secret	B-Application
of	I-Application
the	I-Application
Oracle	I-Application
"	O
and	O
"	O
The	B-Application
Armageddon	I-Application
Machine	I-Application
"	O
,	O
and	O
stylized	O
as	O
Commander	O
Keen	O
in	O
Goodbye	O
,	O
Galaxy	O
!,	O
it	O
was	O
developed	O
by	O
id	O
and	O
published	O
through	O
Apogee	O
.	O
</s>
<s>
Like	O
the	O
first	O
trilogy	O
of	O
episodes	O
,	O
"	O
Secret	B-Application
of	I-Application
the	I-Application
Oracle	I-Application
"	O
was	O
released	O
for	O
free	O
,	O
and	O
the	O
other	O
episode	O
sold	O
by	O
Apogee	O
.	O
</s>
<s>
The	O
game	O
incorporates	O
a	O
more	O
polished	O
version	O
of	O
the	O
graphical	O
updates	O
in	O
Keen	B-Application
Dreams	I-Application
,	O
along	O
with	O
further	O
gameplay	O
changes	O
and	O
additions	O
.	O
</s>
<s>
Commander	B-Application
Keen	I-Application
in	I-Application
Aliens	I-Application
Ate	I-Application
My	I-Application
Babysitter	I-Application
is	O
the	O
final	O
id-developed	O
game	O
,	O
released	O
in	O
December	O
1991	O
for	O
MS-DOS	B-Application
.	O
</s>
<s>
Originally	O
planned	O
to	O
be	O
the	O
third	O
episode	O
of	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
and	O
sixth	O
episode	O
overall	O
,	O
it	O
was	O
changed	O
before	O
development	O
began	O
to	O
be	O
a	O
stand-alone	O
game	O
—	O
stylized	O
as	O
Commander	B-Application
Keen	I-Application
in	I-Application
Aliens	I-Application
Ate	I-Application
My	I-Application
Babysitter	I-Application
!	I-Application
—	O
published	O
as	O
a	O
retail	O
title	O
through	O
FormGen	O
.	O
</s>
<s>
Due	O
to	O
differing	O
timelines	O
between	O
FormGen	O
and	O
Apogee	O
,	O
despite	O
being	O
numbered	O
as	O
the	O
sixth	O
episode	O
it	O
was	O
developed	O
in	O
between	O
the	O
fourth	O
and	O
fifth	O
;	O
it	O
also	O
features	O
a	O
modified	O
engine	O
from	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
.	O
</s>
<s>
Commander	B-Application
Keen	I-Application
was	O
released	O
on	O
May	O
30	O
,	O
2001	O
for	O
the	O
Game	B-Device
Boy	I-Device
Color	I-Device
.	O
</s>
<s>
The	O
idea	O
for	O
a	O
Game	B-Device
Boy	I-Device
Color	I-Device
Keen	O
game	O
came	O
from	O
John	O
Carmack	O
and	O
id	O
,	O
who	O
approached	O
Activision	O
,	O
which	O
in	O
turn	O
proposed	O
Palmer	O
as	O
the	O
developer	O
.	O
</s>
<s>
After	O
the	O
release	O
of	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
and	O
Aliens	B-Application
Ate	I-Application
My	I-Application
Babysitter	I-Application
in	O
1991	O
,	O
id	O
Software	O
planned	O
to	O
make	O
a	O
third	O
set	O
of	O
episodes	O
for	O
the	O
following	O
December	O
,	O
titled	O
Commander	B-Application
Keen	I-Application
in	O
The	O
Universe	O
is	O
Toast	O
!	O
.	O
</s>
<s>
Beyond	O
the	O
proposed	O
title	O
and	O
release	O
date	O
,	O
shown	O
in	O
the	O
epilogue	O
of	O
the	O
two	O
games	O
,	O
no	O
design	O
work	O
was	O
completed	O
before	O
the	O
game	O
was	O
cancelled	O
due	O
to	O
the	O
success	O
of	O
id	O
's	O
Wolfenstein	B-Application
3D	I-Application
(	O
1992	O
)	O
and	O
development	O
focus	O
on	O
3D	O
first-person	O
shooters	O
such	O
as	O
Doom	B-Application
(	O
1993	O
)	O
.	O
</s>
<s>
John	O
Carmack	O
noted	O
in	O
1999	O
,	O
when	O
referencing	O
the	O
project	O
that	O
became	O
the	O
Game	B-Device
Boy	I-Device
Color	I-Device
game	O
,	O
that	O
the	O
original	O
developers	O
of	O
Keen	O
were	O
unlikely	O
to	O
ever	O
work	O
together	O
again	O
on	O
another	O
game	O
.	O
</s>
<s>
On	O
June	O
9	O
,	O
2019	O
at	O
Bethesda	O
's	O
E3	O
2019	O
conference	O
for	O
iOS	B-Application
and	O
Android	B-Application
devices	O
,	O
a	O
new	O
game	O
in	O
the	O
series	O
was	O
announced	O
,	O
again	O
titled	O
Commander	B-Application
Keen	I-Application
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
initial	O
releases	O
of	O
the	O
games	O
,	O
several	O
compilation	O
releases	O
have	O
been	O
published	O
:	O
the	O
id	O
Anthology	O
compilation	O
in	O
1996	O
,	O
which	O
includes	O
all	O
seven	O
episodes	O
developed	O
by	O
id	O
or	O
Ideas	O
from	O
the	O
Deep	O
;	O
a	O
compilation	O
release	O
by	O
Apogee	O
in	O
1998	O
of	O
the	O
five	O
episodes	O
of	O
Invasion	B-Application
of	I-Application
the	I-Application
Vorticons	I-Application
and	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
;	O
and	O
the	O
3D	O
Realms	O
Anthology	O
in	O
2014	O
,	O
which	O
also	O
includes	O
Vorticons	B-Application
and	O
Galaxy	O
.	O
</s>
<s>
The	O
Apogee-published	O
episodes	O
have	O
also	O
been	O
released	O
for	O
modern	O
computers	O
through	O
a	O
DOS	B-Device
emulator	O
,	O
and	O
sold	O
through	O
Steam	B-Application
since	O
2007	O
as	O
the	O
Commander	B-Application
Keen	I-Application
Complete	O
Pack	O
.	O
</s>
<s>
All	O
of	O
the	O
games	O
in	O
the	O
Commander	B-Application
Keen	I-Application
series	I-Application
are	O
side-scrolling	O
platform	O
video	O
games	O
:	O
the	O
majority	O
of	O
the	O
game	O
features	O
the	O
player-controlled	O
Commander	B-Application
Keen	I-Application
viewed	O
from	O
the	O
side	O
while	O
moving	O
on	O
a	O
two-dimensional	O
plane	O
.	O
</s>
<s>
The	O
player	O
can	O
move	O
left	O
and	O
right	O
and	O
can	O
jump	O
;	O
in	O
every	O
episode	O
besides	O
Keen	B-Application
Dreams	I-Application
they	O
can	O
also	O
use	O
a	O
pogo	O
stick	O
to	O
bounce	O
continuously	O
and	O
jump	O
higher	O
than	O
they	O
can	O
normally	O
with	O
the	O
correct	O
timing	O
.	O
</s>
<s>
Keen	B-Application
Dreams	I-Application
and	O
later	O
games	O
add	O
fireman	O
's	O
poles	O
that	O
Keen	O
can	O
climb	O
up	O
or	O
down	O
,	O
and	O
with	O
the	O
exception	O
of	O
the	O
2001	O
Commander	B-Application
Keen	I-Application
also	O
show	O
the	O
platforms	O
viewed	O
from	O
slightly	O
above	O
so	O
as	O
to	O
give	O
a	O
pseudo-3D	O
effect	O
.	O
</s>
<s>
Throughout	O
the	O
series	O
,	O
once	O
entered	O
,	O
the	O
only	O
way	O
to	O
exit	O
a	O
level	O
is	O
to	O
reach	O
the	O
end	O
,	O
though	O
for	O
Keen	B-Application
Dreams	I-Application
and	O
episodes	O
four	O
through	O
six	O
the	O
player	O
can	O
save	O
and	O
return	O
to	O
the	O
middle	O
of	O
a	O
level	O
,	O
rather	O
than	O
only	O
between	O
levels	O
like	O
the	O
other	O
games	O
.	O
</s>
<s>
Invasion	B-Application
of	I-Application
the	I-Application
Vorticons	I-Application
features	O
a	O
raygun	O
that	O
Keen	O
can	O
use	O
ammo	O
for	O
to	O
kill	O
enemies	O
;	O
Keen	B-Application
Dreams	I-Application
exchanges	O
this	O
for	O
flower	O
power	O
pellets	O
that	O
temporarily	O
stun	O
enemies	O
when	O
thrown	O
,	O
episodes	O
four	O
through	O
six	O
use	O
a	O
stun	O
gun	O
that	O
permanently	O
stuns	O
enemies	O
,	O
and	O
the	O
2001	O
Commander	B-Application
Keen	I-Application
has	O
a	O
stun	O
gun	O
that	O
temporarily	O
stuns	O
enemies	O
unless	O
they	O
are	O
then	O
killed	O
with	O
a	O
pogo	O
jump	O
.	O
</s>
<s>
In	O
the	O
first	O
episode	O
,	O
"	O
Marooned	O
on	O
Mars	O
"	O
,	O
eight-year-old	O
Billy	B-Application
Blaze	I-Application
,	O
a	O
child	O
genius	O
,	O
builds	O
a	O
spaceship	O
(	O
the	O
"	O
Beans	O
with	O
Bacon	O
Megarocket	O
"	O
)	O
and	O
puts	O
on	O
his	O
older	O
brother	O
's	O
football	O
helmet	O
to	O
become	O
Commander	B-Application
Keen	I-Application
.	O
</s>
<s>
One	O
night	O
while	O
his	O
parents	O
are	O
out	O
of	O
the	O
house	O
he	O
flies	O
to	O
Mars	O
to	O
explore	O
;	O
while	O
away	O
from	O
the	O
ship	O
the	O
Vorticons	B-Application
steal	O
four	O
vital	O
components	O
and	O
hide	O
them	O
in	O
Martian	O
cities	O
.	O
</s>
<s>
Keen	O
journeys	O
through	O
Martian	O
cities	O
and	O
outposts	O
to	O
find	O
the	O
components	O
,	O
despite	O
the	O
efforts	O
of	O
Martians	O
and	O
robots	O
;	O
the	O
final	O
component	O
is	O
guarded	O
by	O
a	O
Vorticon	B-Application
.	O
</s>
<s>
Keen	O
returns	O
to	O
Earth	O
—	O
discovering	O
a	O
Vorticon	B-Application
mothership	I-Application
in	O
orbit	O
—	O
and	O
beats	O
his	O
parents	O
home	O
.	O
</s>
<s>
In	O
"	O
The	O
Earth	O
Explodes	O
"	O
he	O
travels	O
through	O
the	O
mothership	O
and	O
disables	O
its	O
weapons	O
,	O
at	O
the	O
end	O
discovering	O
that	O
the	O
Vorticons	B-Application
are	O
being	O
mind-controlled	O
by	O
the	O
mysterious	O
Grand	B-Application
Intellect	I-Application
,	O
who	O
is	O
actually	O
behind	O
the	O
attack	O
on	O
Earth	O
.	O
</s>
<s>
In	O
"	O
Keen	O
Must	O
Die	O
"	O
he	O
fights	O
through	O
the	O
cities	O
and	O
outposts	O
of	O
the	O
Vorticon	B-Application
home	O
planet	O
to	O
reach	O
the	O
Grand	B-Application
Intellect	I-Application
,	O
who	O
is	O
revealed	O
to	O
be	O
his	O
school	O
rival	O
Mortimer	B-Application
McMire	I-Application
,	O
who	O
he	O
then	O
defeats	O
.	O
</s>
<s>
In	O
Keen	B-Application
Dreams	I-Application
,	O
which	O
is	O
set	O
outside	O
of	O
the	O
main	O
continuity	O
,	O
Keen	O
falls	O
asleep	O
after	O
dinner	O
and	O
wakes	O
up	O
in	O
his	O
pajamas	O
in	O
bed	O
on	O
top	O
of	O
a	O
hill	O
.	O
</s>
<s>
The	O
main	O
series	O
of	O
games	O
continues	O
in	O
"	O
Secret	B-Application
of	I-Application
the	I-Application
Oracle	I-Application
"	O
,	O
where	O
Keen	O
builds	O
a	O
faster-than-light	O
radio	O
and	O
overhears	O
plans	O
by	O
a	O
race	O
of	O
aliens	O
known	O
as	O
the	O
Shikadi	O
to	O
destroy	O
the	O
galaxy	O
.	O
</s>
<s>
Keen	O
fights	O
through	O
the	O
outposts	O
and	O
temples	O
of	O
the	O
Shadowlands	O
,	O
rescuing	O
the	O
Gnosticenes	O
,	O
and	O
the	O
Oracle	O
then	O
tells	O
Keen	O
that	O
the	O
Shikadi	O
are	O
"	O
shadow	O
beings	O
from	O
the	O
far	O
side	O
of	O
the	O
galaxy	O
"	O
who	O
are	O
building	O
an	O
Armageddon	B-Application
Machine	I-Application
at	O
Korath	O
III	O
to	O
blow	O
up	O
the	O
galaxy	O
and	O
rebuild	O
it	O
as	O
they	O
wish	O
afterwards	O
.	O
</s>
<s>
In	O
"	O
The	B-Application
Armageddon	I-Application
Machine	I-Application
"	O
,	O
Keen	O
infiltrates	O
the	O
titular	O
space	O
station	O
to	O
disable	O
it	O
,	O
destroying	O
the	O
subsystems	O
of	O
the	O
machine	O
located	O
in	O
each	O
level	O
.	O
</s>
<s>
When	O
he	O
finishes	O
,	O
he	O
finds	O
that	O
the	O
"	O
Gannalech	O
"	O
that	O
was	O
leading	O
the	O
Shikadi	O
was	O
the	O
Grand	B-Application
Intellect	I-Application
McMire	O
,	O
who	O
had	O
escaped	O
Keen	O
in	O
Vorticons	B-Application
by	O
leaving	O
behind	O
an	O
android	B-Application
in	O
his	O
place	O
.	O
</s>
<s>
Aliens	B-Application
Ate	I-Application
My	I-Application
Babysitter	I-Application
is	O
set	O
around	O
the	O
same	O
time	O
,	O
though	O
it	O
is	O
unclear	O
whether	O
it	O
is	O
actually	O
after	O
the	O
events	O
of	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
;	O
in	O
it	O
,	O
the	O
alien	O
Bloogs	O
of	O
Fribbulus	O
Xax	O
kidnap	O
Keen	O
's	O
babysitter	O
and	O
plan	O
to	O
eat	O
her	O
.	O
</s>
<s>
While	O
the	O
planned	O
trilogy	O
that	O
would	O
cover	O
that	O
plot	O
,	O
The	O
Universe	O
is	O
Toast	O
,	O
was	O
never	O
developed	O
,	O
the	O
Game	B-Device
Boy	I-Device
Color	I-Device
Commander	B-Application
Keen	I-Application
has	O
a	O
sub-space	O
anomaly	O
disrupting	O
life	O
on	O
Earth	O
as	O
an	O
effect	O
of	O
a	O
plot	O
by	O
the	O
Bloogs	O
,	O
Shikadi	O
,	O
and	O
Droidicus	O
,	O
led	O
by	O
McMire	O
,	O
to	O
destroy	O
the	O
universe	O
.	O
</s>
<s>
At	O
the	O
time	O
,	O
IBM-compatible	O
general-purpose	O
computers	O
were	O
not	O
able	O
to	O
replicate	O
the	O
common	O
feat	O
of	O
video	B-Device
game	I-Device
consoles	I-Device
such	O
as	O
the	O
Nintendo	O
Entertainment	O
System	O
,	O
which	O
were	O
capable	O
of	O
redrawing	O
the	O
entire	O
screen	O
fast	O
enough	O
for	O
a	O
side-scrolling	O
video	O
game	O
due	O
to	O
their	O
specialized	O
hardware	O
.	O
</s>
<s>
He	O
discussed	O
the	O
idea	O
with	O
coworker	O
Tom	O
Hall	O
,	O
who	O
encouraged	O
him	O
to	O
demonstrate	O
it	O
by	O
recreating	O
the	O
first	O
level	O
of	O
the	O
recent	O
Super	B-Application
Mario	I-Application
Bros	I-Application
.	I-Application
3	I-Application
on	O
a	O
computer	O
.	O
</s>
<s>
The	O
pair	O
did	O
so	O
in	O
a	O
single	O
overnight	O
session	O
,	O
with	O
Hall	O
recreating	O
the	O
graphics	O
of	O
the	O
game	O
—	O
replacing	O
the	O
player	O
character	O
of	O
Mario	B-Application
with	O
Dangerous	B-Application
Dave	I-Application
,	O
a	O
character	O
from	O
an	B-Application
eponymous	I-Application
previous	I-Application
Gamer	I-Application
's	I-Application
Edge	I-Application
game	I-Application
—	O
while	O
Carmack	O
optimized	O
the	O
code	O
.	O
</s>
<s>
The	O
next	O
morning	O
on	O
September	O
20	O
,	O
the	O
resulting	O
game	O
,	O
Dangerous	B-Application
Dave	I-Application
in	O
Copyright	O
Infringement	O
,	O
was	O
shown	O
to	O
their	O
other	O
coworker	O
John	O
Romero	O
.	O
</s>
<s>
Romero	O
recognized	O
Carmack	O
's	O
idea	O
as	O
a	O
major	O
accomplishment	O
:	O
Nintendo	O
was	O
one	O
of	O
the	O
most	O
successful	O
companies	O
in	O
Japan	O
,	O
largely	O
due	O
to	O
the	O
success	O
of	O
their	O
Mario	B-Application
franchise	I-Application
,	O
and	O
the	O
ability	O
to	O
replicate	O
the	O
gameplay	O
of	O
the	O
series	O
on	O
a	O
computer	O
could	O
have	O
large	O
implications	O
.	O
</s>
<s>
The	O
manager	O
of	O
the	O
team	O
and	O
fellow	O
programmer	O
,	O
Jay	O
Wilbur	O
,	O
recommended	O
that	O
they	O
take	O
the	O
demo	O
to	O
Nintendo	O
itself	O
,	O
to	O
position	O
themselves	O
as	O
capable	O
of	O
building	O
a	O
PC	O
version	O
of	O
Super	B-Application
Mario	I-Application
Bros	O
.	O
for	O
the	O
company	O
.	O
</s>
<s>
The	O
response	O
from	O
Nintendo	O
a	O
few	O
weeks	O
later	O
was	O
not	O
as	O
hoped	O
for	O
,	O
however	O
;	O
while	O
Nintendo	O
was	O
impressed	O
with	O
their	O
efforts	O
,	O
they	O
wanted	O
the	O
Mario	B-Application
series	I-Application
to	O
remain	O
exclusive	O
to	O
Nintendo	O
consoles	O
.	O
</s>
<s>
Around	O
the	O
same	O
time	O
as	O
the	O
group	O
was	O
rejected	O
by	O
Nintendo	O
,	O
Romero	O
was	O
approached	O
by	O
Scott	O
Miller	O
of	O
Apogee	O
Software	O
,	O
who	O
wanted	O
him	O
to	O
publish	O
more	O
levels	O
for	O
his	O
previous	O
Pyramids	O
of	O
Egypt	O
—	O
an	O
adventure	O
game	O
where	O
the	O
player	O
navigates	O
mazes	O
while	O
avoiding	O
Egyptian-themed	O
traps	O
and	O
monsters	O
—	O
through	O
Apogee	O
's	O
shareware	B-License
model	O
.	O
</s>
<s>
Romero	O
said	O
he	O
could	O
not	O
,	O
as	O
Pyramids	O
of	O
Egypt	O
was	O
owned	O
by	O
Softdisk	O
,	O
but	O
that	O
it	O
did	O
not	O
matter	O
as	O
the	O
game	O
he	O
was	O
now	O
working	O
on	O
was	O
much	O
better	O
,	O
and	O
sent	O
Miller	O
the	O
Mario	B-Application
demo	O
.	O
</s>
<s>
Miller	O
was	O
impressed	O
,	O
and	O
the	O
team	O
agreed	O
to	O
create	O
a	O
new	O
game	O
for	O
Apogee	O
before	O
Christmas	O
of	O
1990	O
—	O
only	O
a	O
few	O
months	O
away	O
—	O
split	O
into	O
three	O
parts	O
to	O
match	O
Apogee	O
's	O
shareware	B-License
model	O
of	O
giving	O
away	O
the	O
first	O
part	O
for	O
free	O
to	O
attract	O
interest	O
in	O
the	O
whole	O
.	O
</s>
<s>
Hall	O
suggested	O
a	O
console-style	O
platformer	O
in	O
the	O
vein	O
of	O
Super	B-Application
Mario	I-Application
Bros.	O
,	O
as	O
they	O
had	O
the	O
technology	O
made	O
for	O
it	O
;	O
he	O
further	O
recommended	O
a	O
science	O
fiction	O
theme	O
,	O
and	O
developed	O
a	O
short	O
introduction	O
that	O
convinced	O
the	O
team	O
to	O
make	O
Commander	B-Application
Keen	I-Application
in	I-Application
Invasion	I-Application
of	I-Application
the	I-Application
Vorticons	I-Application
.	O
</s>
<s>
The	O
Ideas	O
from	O
the	O
Deep	O
team	O
could	O
not	O
afford	O
to	O
leave	O
their	O
jobs	O
to	O
work	O
on	O
the	O
game	O
full-time	O
,	O
so	O
they	O
continued	O
to	O
work	O
at	O
Softdisk	O
,	O
spending	O
their	O
time	O
on	O
the	O
Gamer	O
's	O
Edge	O
games	O
during	O
the	O
day	O
and	O
on	O
Commander	B-Application
Keen	I-Application
at	O
night	O
and	O
weekends	O
using	O
Softdisk	O
computers	O
.	O
</s>
<s>
Ideas	O
from	O
the	O
Deep	O
spent	O
nearly	O
every	O
waking	O
moment	O
when	O
they	O
were	O
not	O
working	O
at	O
Softdisk	O
from	O
October	O
through	O
December	O
1990	O
working	O
on	O
Commander	B-Application
Keen	I-Application
,	O
with	O
Wilbur	O
forcing	O
them	O
to	O
eat	O
and	O
take	O
breaks	O
.	O
</s>
<s>
The	O
team	O
separated	O
the	O
game	O
from	O
its	O
Super	B-Application
Mario	I-Application
Bros	O
.	O
roots	O
by	O
adding	O
non-linear	O
exploration	O
and	O
additional	O
mechanics	O
like	O
the	O
pogo	O
stick	O
.	O
</s>
<s>
A	O
suggestion	O
from	O
Miller	O
that	O
part	O
of	O
the	O
popularity	O
of	O
Super	B-Application
Mario	I-Application
Bros	O
was	O
the	O
presence	O
of	O
secrets	O
and	O
hidden	O
areas	O
in	O
the	O
game	O
led	O
Hall	O
to	O
add	O
several	O
secrets	O
,	O
such	O
as	O
an	O
entire	O
hidden	O
level	O
in	O
the	O
first	O
episode	O
,	O
and	O
the	O
"	O
Galactic	O
Alphabet	O
"	O
.	O
</s>
<s>
The	O
level	O
maps	O
were	O
designed	O
using	O
a	O
custom-made	O
program	O
called	O
Tile	O
Editor	O
(	O
TEd	O
)	O
,	O
which	O
was	O
first	O
created	O
for	O
Dangerous	B-Application
Dave	I-Application
and	O
was	O
used	O
for	O
the	O
entire	O
Keen	O
series	O
as	O
well	O
as	O
several	O
other	O
games	O
.	O
</s>
<s>
Strongly	O
encouraged	O
by	O
the	O
updates	O
the	O
team	O
was	O
sending	O
him	O
,	O
he	O
began	O
heavily	O
advertising	O
the	O
game	O
in	O
all	O
of	O
the	O
bulletin	B-Application
board	I-Application
systems	I-Application
(	O
BBS	O
)	O
and	O
game	O
magazines	O
he	O
had	O
access	O
to	O
.	O
</s>
<s>
Ideas	O
from	O
the	O
Deep	O
,	O
now	O
founded	O
as	O
id	O
Software	O
,	O
used	O
some	O
of	O
these	O
games	O
to	O
prototype	O
ideas	O
for	O
their	O
own	O
games	O
,	O
including	O
in	O
late	O
spring	O
of	O
1991	O
Keen	B-Application
Dreams	I-Application
,	O
which	O
they	O
used	O
to	O
develop	O
new	O
systems	O
for	O
their	O
next	O
set	O
of	O
major	O
episodes	O
of	O
the	O
series	O
.	O
</s>
<s>
The	O
team	O
reprised	O
their	O
roles	O
from	O
the	O
first	O
game	O
,	O
and	O
prototyped	O
an	O
increase	O
in	O
graphical	O
quality	O
,	O
a	O
pseudo-3D	O
view	O
rather	O
than	O
a	O
side-on	O
view	O
,	O
ramps	O
rather	O
than	O
solely	O
flat	O
surfaces	O
,	O
support	O
for	O
sound	B-Device
cards	I-Device
,	O
and	O
changes	O
to	O
the	O
design	O
based	O
on	O
player	O
feedback	O
.	O
</s>
<s>
Once	O
the	O
game	O
engine	O
and	O
design	O
changes	O
were	O
completed	O
,	O
Keen	B-Application
Dreams	I-Application
was	O
completed	O
in	O
less	O
than	O
a	O
month	O
even	O
as	O
the	O
team	O
simultaneously	O
worked	O
on	O
another	O
game	O
.	O
</s>
<s>
Beginning	O
development	O
in	O
the	O
June	O
1991	O
,	O
the	O
team	O
again	O
reprised	O
their	O
roles	O
for	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
.	O
</s>
<s>
Hall	O
had	O
received	O
feedback	O
from	O
parents	O
who	O
did	O
not	O
like	O
that	O
the	O
enemies	O
in	O
Vorticons	B-Application
left	O
behind	O
corpses	O
instead	O
of	O
disappearing	O
like	O
in	O
other	O
games	O
;	O
he	O
did	O
not	O
want	O
the	O
violence	O
to	O
have	O
no	O
effects	O
,	O
and	O
so	O
in	O
Dreams	O
had	O
replaced	O
the	O
raygun	O
with	O
pellets	O
that	O
temporarily	O
stunned	O
enemies	O
.	O
</s>
<s>
He	O
was	O
not	O
satisfied	O
with	O
this	O
change	O
,	O
and	O
while	O
considering	O
ways	O
to	O
remove	O
Keen	O
's	O
parents	O
during	O
the	O
introduction	O
for	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
,	O
came	O
up	O
with	O
a	O
stun	O
gun	O
which	O
would	O
leave	O
behind	O
permanently	O
stunned	O
enemies	O
.	O
</s>
<s>
Additionally	O
,	O
music	O
,	O
which	O
was	O
missing	O
in	O
prior	O
Keen	O
games	O
,	O
was	O
added	O
to	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
,	O
composed	O
by	O
Bobby	O
Prince	O
.	O
</s>
<s>
The	O
game	O
,	O
episodes	O
four	O
though	O
six	O
,	O
was	O
intended	O
to	O
be	O
published	O
as	O
a	O
set	O
named	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
in	O
the	O
same	O
manner	O
as	O
the	O
first	O
one	O
:	O
released	O
through	O
Apogee	O
,	O
with	O
episode	O
four	O
released	O
for	O
free	O
in	O
order	O
to	O
spur	O
interest	O
in	O
purchasing	O
the	O
other	O
two	O
episodes	O
.	O
</s>
<s>
By	O
August	O
they	O
had	O
completed	O
a	O
beta	O
version	O
of	O
episode	O
four	O
,	O
"	O
Secret	B-Application
of	I-Application
the	I-Application
Oracle	I-Application
"	O
,	O
and	O
Romero	O
sent	O
it	O
off	O
to	O
a	O
fan	O
he	O
had	O
met	O
from	O
Canada	O
,	O
Mark	O
Rein	O
,	O
who	O
had	O
offered	O
to	O
play-test	O
the	O
game	O
.	O
</s>
<s>
Within	O
a	O
few	O
weeks	O
of	O
being	O
hired	O
,	O
Rein	O
made	O
a	O
deal	O
to	O
get	O
id	O
into	O
the	O
commercial	O
market	O
:	O
to	O
take	O
the	O
sixth	O
episode	O
and	O
make	O
it	O
a	O
stand-alone	O
game	O
,	O
published	O
as	O
a	O
retail	O
title	O
through	O
FormGen	O
instead	O
of	O
part	O
of	O
a	O
shareware	B-License
trilogy	O
.	O
</s>
<s>
Id	O
signed	O
the	O
deal	O
,	O
but	O
Scott	O
Miller	O
of	O
Apogee	O
was	O
dismayed	O
;	O
he	O
felt	O
that	O
not	O
having	O
a	O
full	O
trilogy	O
for	O
the	O
shareware	B-License
game	O
would	O
hurt	O
sales	O
.	O
</s>
<s>
There	O
,	O
they	O
worked	O
on	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
,	O
their	O
remaining	O
Softdisk	O
games	O
,	O
and	O
the	O
now	O
standalone	O
Commander	B-Application
Keen	I-Application
in	I-Application
Aliens	I-Application
Ate	I-Application
My	I-Application
Babysitter	I-Application
between	O
August	O
and	O
December	O
.	O
</s>
<s>
Despite	O
being	O
listed	O
numerically	O
as	O
the	O
sixth	O
episode	O
,	O
due	O
to	O
it	O
having	O
a	O
different	O
publisher	O
and	O
schedule	O
Aliens	B-Application
Ate	I-Application
My	I-Application
Babysitter	I-Application
was	O
developed	O
after	O
"	O
Secret	B-Application
of	I-Application
the	I-Application
Oracle	I-Application
"	O
but	O
before	O
"	O
The	B-Application
Armageddon	I-Application
Machine	I-Application
"	O
;	O
the	O
fifth	O
episode	O
,	O
however	O
,	O
was	O
created	O
within	O
one	O
month	O
.	O
</s>
<s>
Another	O
trilogy	O
of	O
episodes	O
,	O
titled	O
The	O
Universe	O
Is	O
Toast	O
,	O
was	O
planned	O
for	O
December	O
1992	O
;	O
id	O
worked	O
on	O
it	O
for	O
a	O
couple	O
of	O
weeks	O
,	O
before	O
shifting	O
focus	O
to	O
Wolfenstein	B-Application
3D	I-Application
(	O
1992	O
)	O
.	O
</s>
<s>
Hall	O
proposed	O
reviving	O
the	O
project	O
after	O
Wolfenstein	B-Application
was	O
completed	O
,	O
but	O
the	O
team	O
moved	O
on	O
to	O
Doom	B-Application
(	O
1993	O
)	O
instead	O
.	O
</s>
<s>
In	O
October	O
1999	O
during	O
an	O
online	O
question	O
and	O
answer	O
session	O
,	O
John	O
Carmack	O
,	O
while	O
discussing	O
that	O
the	O
original	O
founders	O
of	O
id	O
Software	O
were	O
unlikely	O
to	O
ever	O
work	O
together	O
on	O
a	O
game	O
again	O
,	O
mentioned	O
that	O
he	O
was	O
considering	O
the	O
idea	O
of	O
making	O
a	O
Commander	B-Application
Keen	I-Application
game	O
for	O
the	O
Game	B-Device
Boy	I-Device
Color	I-Device
handheld	B-Application
game	I-Application
console	I-Application
.	O
</s>
<s>
Activision	O
formally	O
announced	O
at	O
the	O
start	O
of	O
May	O
2001	O
that	O
a	O
new	O
Commander	B-Application
Keen	I-Application
game	O
had	O
been	O
developed	O
by	O
David	O
A	O
.	O
Palmer	O
Productions	O
,	O
and	O
would	O
be	O
released	O
at	O
the	O
end	O
of	O
the	O
month	O
.	O
</s>
<s>
An	O
interview	O
the	O
following	O
week	O
with	O
founder	O
David	O
A	O
.	O
Palmer	O
explained	O
that	O
the	O
original	O
idea	O
for	O
the	O
game	O
came	O
from	O
id	O
,	O
who	O
approached	O
Activision	O
to	O
produce	O
it	O
;	O
Activision	O
in	O
turn	O
recommended	O
Palmer	O
as	O
the	O
developer	O
for	O
the	O
project	O
as	O
they	O
had	O
been	O
attempting	O
to	O
get	O
an	O
agreement	O
with	O
id	O
and	O
Activision	O
for	O
several	O
years	O
for	O
his	O
studio	O
to	O
make	O
a	O
Game	B-Device
Boy	I-Device
Color	I-Device
version	O
of	O
several	O
of	O
their	O
games	O
.	O
</s>
<s>
Commander	B-Application
Keen	I-Application
in	I-Application
Invasion	I-Application
of	I-Application
the	I-Application
Vorticons	I-Application
was	O
an	O
immediate	O
hit	O
for	O
Apogee	O
:	O
the	O
company	O
's	O
previous	O
sales	O
levels	O
had	O
been	O
around	O
US$	O
7,000	O
per	O
month	O
,	O
but	O
by	O
Christmas	O
Keen	O
already	O
had	O
sales	O
of	O
almost	O
US$	O
30,000	O
.	O
</s>
<s>
After	O
its	O
release	O
in	O
December	O
1991	O
,	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
met	O
with	O
sales	O
"	O
about	O
a	O
third	O
"	O
of	O
the	O
original	O
trilogy	O
.	O
</s>
<s>
Scott	O
Miller	O
of	O
Apogee	O
blamed	O
the	O
falling	O
sales	O
on	O
the	O
lack	O
of	O
a	O
third	O
episode	O
,	O
which	O
he	O
felt	O
undercut	O
the	O
shareware	B-License
model	O
of	O
the	O
game	O
.	O
</s>
<s>
Tom	O
Hall	O
has	O
also	O
claimed	O
that	O
the	O
split	O
hurt	O
the	O
sales	O
of	O
the	O
shareware	B-License
episodes	O
,	O
though	O
he	O
has	O
said	O
that	O
"	O
they	O
still	O
did	O
decently	O
,	O
though	O
"	O
.	O
</s>
<s>
PC	O
Zone	O
,	O
in	O
its	O
first	O
issue	O
in	O
1993	O
,	O
quoted	O
shareware	B-License
distributors	O
as	O
saying	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
was	O
one	O
of	O
the	O
top	O
shareware	B-License
sellers	O
of	O
1992	O
,	O
behind	O
Wolfenstein	B-Application
3D	I-Application
.	O
</s>
<s>
Hall	O
has	O
claimed	O
"	O
The	B-Application
Armageddon	I-Application
Machine	I-Application
"	O
as	O
the	O
best	O
Commander	B-Application
Keen	I-Application
episode	O
and	O
his	O
favorite	O
.	O
</s>
<s>
Aliens	B-Application
Ate	I-Application
My	I-Application
Babysitter	I-Application
also	O
did	O
not	O
sell	O
as	O
well	O
as	O
hoped	O
for	O
by	O
id	O
,	O
which	O
the	O
team	O
partially	O
blamed	O
on	O
what	O
they	O
felt	O
was	O
terrible	O
box	O
art	O
done	O
by	O
a	O
company	O
that	O
had	O
previously	O
designed	O
packaging	O
for	O
Lipton	O
tea	O
.	O
</s>
<s>
PC	O
Zone	O
also	O
stated	O
that	O
the	O
sales	O
of	O
Aliens	O
through	O
shareware	B-License
distributors	O
was	O
one	O
of	O
the	O
highest	O
in	O
the	O
shareware	B-License
market	O
in	O
1993	O
.	O
</s>
<s>
In	O
October	O
1992	O
,	O
the	O
Shareware	B-Application
Industry	I-Application
Awards	I-Application
gave	O
the	O
Commander	B-Application
Keen	I-Application
series	I-Application
the	O
"	O
Best	O
Entertainment	O
Software	O
and	O
Best	O
Overall	O
"	O
award	O
.	O
</s>
<s>
A	O
review	O
of	O
the	O
entire	O
Commander	B-Application
Keen	I-Application
series	I-Application
in	O
1993	O
by	O
Sandy	O
Petersen	O
in	O
the	O
first	O
"	O
Eye	O
of	O
the	O
Monitor	O
"	O
column	O
for	O
Dragon	O
described	O
the	O
series	O
as	O
action	O
games	O
with	O
"	O
hilarious	O
graphics	O
"	O
.	O
</s>
<s>
Acknowledging	O
its	O
debt	O
to	O
Super	B-Application
Mario	I-Application
Bros.	O
,	O
he	O
called	O
it	O
,	O
especially	O
Goodbye	B-Application
,	I-Application
Galaxy	I-Application
,	O
"	O
one	O
of	O
the	O
best	O
games	O
of	O
its	O
type	O
"	O
and	O
praised	O
it	O
for	O
not	O
being	O
"	O
mindlessly	O
hard	O
"	O
,	O
instead	O
requiring	O
some	O
thought	O
to	O
play	O
through	O
,	O
and	O
especially	O
for	O
the	O
humor	O
in	O
the	O
graphics	O
and	O
gameplay	O
.	O
</s>
<s>
According	O
to	O
Steam	B-Application
Spy	O
,	O
as	O
of	O
June	O
2016	O
there	O
are	O
approximately	O
200,000	O
owners	O
of	O
the	O
2007	O
Commander	B-Application
Keen	I-Application
Complete	O
Pack	O
on	O
Steam	B-Application
,	O
and	O
approximately	O
80,000	O
owners	O
of	O
the	O
Keen	B-Application
Dreams	I-Application
release	O
.	O
</s>
<s>
The	O
2001	O
Commander	B-Application
Keen	I-Application
received	O
mixed	O
reviews	O
from	O
critics	O
.	O
</s>
<s>
In	O
the	O
summer	O
of	O
1991	O
,	O
id	O
hosted	O
a	O
seminar	O
for	O
game	O
developers	O
with	O
the	O
intention	O
of	O
licensing	O
the	O
Commander	B-Application
Keen	I-Application
engine	O
;	O
they	O
did	O
so	O
,	O
forming	O
the	O
spiritual	O
predecessor	O
to	O
both	O
QuakeCon	O
and	O
id	O
's	O
standard	O
of	O
licensing	O
their	O
game	O
engines	O
.	O
</s>
<s>
One	O
of	O
the	O
enemies	O
created	O
for	O
"	O
Secret	B-Application
of	I-Application
the	I-Application
Oracle	I-Application
"	O
,	O
the	O
Dopefish	O
,	O
has	O
since	O
the	O
game	O
's	O
release	O
become	O
one	O
of	O
the	O
video	O
game	O
industry	O
's	O
biggest	O
in-jokes	O
,	O
making	O
cameo	O
appearances	O
in	O
other	O
games	O
.	O
</s>
<s>
The	O
Dopefish	O
,	O
which	O
Hall	O
describes	O
as	O
"	O
just	O
a	O
stupid	O
green	O
fish	O
"	O
,	O
is	O
described	O
in	O
"	O
Secret	B-Application
of	I-Application
the	I-Application
Oracle	I-Application
"	O
as	O
"	O
the	O
second-dumbest	O
creature	O
in	O
the	O
universe	O
"	O
.	O
</s>
<s>
The	O
Standard	O
Galactic	O
Alphabet	O
,	O
a	O
writing	O
system	O
used	O
to	O
depict	O
alien	O
languages	O
in	O
the	O
galaxy	O
throughout	O
the	O
series	O
,	O
is	O
used	O
for	O
textual	O
signs	O
and	O
directions	O
and	O
was	O
created	O
by	O
Tom	O
Hall	O
beginning	O
with	O
Invasion	B-Application
of	I-Application
the	I-Application
Vorticons	I-Application
as	O
a	O
way	O
to	O
pass	O
hidden	O
messages	O
to	O
players	O
.	O
</s>
<s>
The	O
Standard	O
Galactic	O
Alphabet	O
also	O
appears	O
in	O
the	O
game	O
Minecraft	B-Application
as	O
the	O
script	O
and	O
symbols	O
used	O
for	O
its	O
Enchanting	O
Table	O
.	O
</s>
<s>
In	O
January	O
2018	O
,	O
John	O
Romero	O
and	O
Tom	O
Hall	O
stated	O
on	O
Twitter	O
that	O
Billy	B-Application
Blaze	I-Application
is	O
the	O
grandson	O
of	O
Wolfenstein	B-Application
protagonist	O
William	O
"	O
B.J.	O
"	O
</s>
<s>
Blazkowicz	O
and	O
the	O
father	O
of	O
Doomguy	O
from	O
Doom	B-Application
.	O
</s>
<s>
Commander	B-Application
Keen	I-Application
himself	O
has	O
appeared	O
or	O
has	O
been	O
referenced	O
in	O
many	O
other	O
video	O
games	O
over	O
the	O
years	O
,	O
including	O
Doom	B-Application
II	I-Application
,	O
Duke	B-Application
Nukem	I-Application
,	O
Bio	B-Application
Menace	I-Application
and	O
more	O
recently	O
in	O
Doom	B-Application
.	O
</s>
<s>
A	O
number	O
of	O
fan-made	O
Commander	B-Application
Keen	I-Application
games	O
have	O
been	O
created	O
since	O
the	O
publication	O
of	O
the	O
original	O
titles	O
,	O
with	O
a	O
fan	O
website	O
,	O
the	O
Public	O
Commander	B-Application
Keen	I-Application
Forum	O
,	O
devoted	O
to	O
their	O
creation	O
,	O
announcement	O
,	O
and	O
discussion	O
.	O
</s>
<s>
Since	O
the	O
release	O
of	O
utilities	O
to	O
modify	O
the	O
levels	O
and	O
graphics	O
in	O
the	O
original	O
Keen	O
series	O
in	O
2002	O
,	O
more	O
than	O
fifty	O
mods	O
have	O
been	O
made	O
,	O
most	O
of	O
which	O
feature	O
Commander	B-Application
Keen	I-Application
as	O
the	O
protagonist	O
.	O
</s>
<s>
In	O
January	O
2013	O
,	O
Tom	O
Hall	O
began	O
development	O
of	O
Worlds	O
of	O
Wander	O
,	O
a	O
tool	O
for	O
creating	O
platform	O
games	O
,	O
and	O
the	O
following	O
month	O
began	O
a	O
Kickstarter	O
campaign	O
for	O
the	O
tool	O
and	O
associated	O
game	O
,	O
Secret	O
Spaceship	O
Club	O
,	O
which	O
he	O
described	O
as	O
a	O
spiritual	O
successor	O
to	O
Commander	B-Application
Keen	I-Application
.	O
</s>
