<s>
Commander	B-Application
Keen	I-Application
in	I-Application
Invasion	I-Application
of	I-Application
the	I-Application
Vorticons	I-Application
is	O
a	O
three-part	O
episodic	O
side-scrolling	O
platform	O
video	O
game	O
developed	O
by	O
Ideas	O
from	O
the	O
Deep	O
(	O
a	O
precursor	O
to	O
id	O
Software	O
)	O
and	O
published	O
by	O
Apogee	O
Software	O
in	O
1990	O
for	O
MS-DOS	B-Application
.	O
</s>
<s>
It	O
is	O
the	O
first	O
set	O
of	O
episodes	O
of	O
the	O
Commander	B-Application
Keen	I-Application
series	O
.	O
</s>
<s>
The	O
game	O
follows	O
the	O
titular	O
Commander	B-Application
Keen	I-Application
,	O
an	O
eight-year-old	O
child	O
genius	O
,	O
as	O
he	O
retrieves	O
the	O
stolen	O
parts	O
of	O
his	O
spaceship	O
from	O
the	O
cities	O
of	O
Mars	O
,	O
prevents	O
a	O
recently	O
arrived	O
alien	O
mothership	O
from	O
destroying	O
landmarks	O
on	O
Earth	O
,	O
and	O
hunts	O
down	O
the	O
leader	O
of	O
the	O
aliens	O
,	O
the	O
Grand	O
Intellect	O
,	O
on	O
the	O
alien	O
home	O
planet	O
.	O
</s>
<s>
In	O
September	O
1990	O
,	O
John	O
Carmack	O
,	O
while	O
working	O
at	O
programming	O
studio	O
Softdisk	O
,	O
developed	O
a	O
way	O
to	O
implement	O
smooth	O
side-scrolling	O
in	O
video	O
games	O
on	O
personal	B-Device
computers	I-Device
(	O
PCs	B-Device
)	O
,	O
which	O
at	O
the	O
time	O
was	O
the	O
province	O
of	O
dedicated	O
home	B-Device
video	I-Device
game	I-Device
consoles	I-Device
.	O
</s>
<s>
Carmack	O
and	O
his	O
coworkers	O
John	O
Romero	O
and	O
Tom	O
Hall	O
,	O
along	O
with	O
Jay	O
Wilbur	O
and	O
Lane	O
Roathe	O
,	O
developed	O
a	O
demo	O
of	O
a	O
PC	O
version	O
of	O
Super	B-Application
Mario	I-Application
Bros	I-Application
.	I-Application
3	I-Application
,	O
but	O
failed	O
to	O
convince	O
Nintendo	O
to	O
invest	O
in	O
a	O
PC	O
port	O
of	O
their	O
game	O
.	O
</s>
<s>
Soon	O
afterwards	O
,	O
however	O
,	O
they	O
were	O
approached	O
by	O
Scott	O
Miller	O
of	O
Apogee	O
Software	O
to	O
develop	O
an	O
original	O
game	O
to	O
be	O
published	O
through	O
the	O
Apogee	O
shareware	B-License
model	O
.	O
</s>
<s>
Apogee	O
,	O
whose	O
monthly	O
sales	O
had	O
been	O
around	O
US$7	O
,	O
000	O
,	O
made	O
US$	O
30,000	O
on	O
Commander	B-Application
Keen	I-Application
alone	O
in	O
the	O
first	O
two	O
weeks	O
and	O
US$	O
60,000	O
per	O
month	O
by	O
June	O
.	O
</s>
<s>
The	O
team	O
founded	O
id	O
Software	O
shortly	O
thereafter	O
and	O
went	O
on	O
to	O
produce	O
another	O
four	O
episodes	O
of	O
the	O
Commander	B-Application
Keen	I-Application
series	O
over	O
the	O
next	O
year	O
.	O
</s>
<s>
The	O
trilogy	O
was	O
lauded	O
by	O
reviewers	O
due	O
to	O
the	O
graphical	O
achievement	O
and	O
humorous	O
style	O
,	O
and	O
id	O
Software	O
went	O
on	O
to	O
develop	O
other	O
successful	O
games	O
,	O
including	O
Wolfenstein	B-Application
3D	I-Application
(	O
1992	O
)	O
and	O
Doom	B-Application
(	O
1993	O
)	O
.	O
</s>
<s>
The	O
Vorticons	B-Application
trilogy	O
has	O
been	O
released	O
as	O
part	O
of	O
several	O
collections	O
by	O
id	O
and	O
Apogee	O
since	O
its	O
first	O
release	O
,	O
and	O
has	O
been	O
sold	O
for	O
modern	O
computers	O
through	O
Steam	B-Application
since	O
2007	O
.	O
</s>
<s>
The	O
three	O
episodes	O
of	O
Commander	B-Application
Keen	I-Application
in	I-Application
Invasion	I-Application
of	I-Application
the	I-Application
Vorticons	I-Application
make	O
up	O
one	O
side-scrolling	O
platform	O
video	O
game	O
:	O
most	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>
All	O
three	O
episodes	O
also	O
include	O
Vorticons	B-Application
,	O
large	O
blue	O
canine-like	O
aliens	O
.	O
</s>
<s>
Touching	O
a	O
hazard	O
or	O
most	O
enemies	O
causes	O
Keen	O
to	O
lose	O
a	O
life	O
,	O
and	O
the	O
game	O
is	O
ended	B-Application
if	O
all	O
of	O
Keen	O
's	O
lives	O
are	O
lost	O
.	O
</s>
<s>
There	O
are	O
also	O
colored	O
keycards	O
that	O
grant	O
access	O
to	O
locked	O
parts	O
of	O
levels	O
,	O
and	O
in	O
the	O
third	O
episode	O
on	O
rare	O
occasions	O
an	O
ankh	B-Application
,	O
which	O
gives	O
Keen	O
temporary	O
invulnerability	O
.	O
</s>
<s>
In	O
the	O
first	O
episode	O
,	O
eight-year-old	O
child	O
Billy	O
Blaze	O
builds	O
a	O
spaceship	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
,	O
he	O
flies	O
to	O
Mars	O
to	O
explore	O
,	O
but	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>
After	O
securing	O
the	O
final	O
component	O
,	O
which	O
is	O
guarded	O
by	O
a	O
Vorticon	B-Application
,	O
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
who	O
discover	O
that	O
he	O
now	O
has	O
a	O
pet	O
Yorp	O
.	O
</s>
<s>
In	O
the	O
second	O
episode	O
,	O
the	O
Vorticon	B-Application
mothership	I-Application
has	O
locked	O
its	O
X-14	O
Tantalus	O
Ray	O
cannons	O
on	O
eight	O
of	O
Earth	O
's	O
landmarks	O
,	O
and	O
Keen	O
journeys	O
to	O
the	O
ship	O
to	O
find	O
and	O
deactivate	O
each	O
of	O
the	O
cannons	O
.	O
</s>
<s>
Keen	O
does	O
so	O
by	O
fighting	O
more	O
varied	O
enemies	O
and	O
hazards	O
and	O
a	O
Vorticon	B-Application
at	O
each	O
cannon	O
's	O
control	O
.	O
</s>
<s>
At	O
the	O
end	O
of	O
the	O
episode	O
,	O
he	O
discovers	O
that	O
the	O
Vorticons	B-Application
are	O
being	O
mind-controlled	O
by	O
the	O
mysterious	O
Grand	O
Intellect	O
,	O
who	O
is	O
actually	O
behind	O
the	O
attack	O
on	O
Earth	O
.	O
</s>
<s>
In	O
the	O
third	O
episode	O
,	O
Keen	O
journeys	O
to	O
the	O
Vorticon	B-Application
homeworld	O
of	O
Vorticon	B-Application
VI	I-Application
to	O
find	O
the	O
Grand	O
Intellect	O
.	O
</s>
<s>
He	O
travels	O
through	O
Vorticon	B-Application
cities	O
and	O
outposts	O
to	O
gain	O
access	O
to	O
the	O
Grand	O
Intellect	O
's	O
lair	O
,	O
fighting	O
mostly	O
against	O
the	O
Vorticons	B-Application
themselves	O
.	O
</s>
<s>
Keen	O
defeats	O
Mortimer	O
and	O
his	O
"	O
Mangling	O
Machine	O
"	O
and	O
frees	O
the	O
Vorticons	B-Application
from	O
mind-control	O
;	O
the	O
Vorticon	B-Application
king	O
and	O
"	O
the	O
other	O
Vorticons	B-Application
you	O
have	O
n't	O
slaughtered	O
"	O
then	O
award	O
him	O
a	O
medal	O
for	O
saving	O
them	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
that	O
of	O
redrawing	O
the	O
entire	O
screen	O
fast	O
enough	O
for	O
a	O
smooth	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
recently	O
released	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	O
eponymous	O
previous	O
Gamer	O
's	O
Edge	O
game	O
—	O
while	O
Carmack	O
optimized	O
the	O
code	O
.	O
</s>
<s>
The	O
next	O
morning	O
,	O
September	O
20	O
,	O
Carmack	O
and	O
Hall	O
showed	O
the	O
resulting	O
game	O
,	O
Dangerous	B-Application
Dave	I-Application
in	O
Copyright	O
Infringement	O
,	O
to	O
another	O
coworker	O
,	O
John	O
Romero	O
.	O
</s>
<s>
Romero	O
recognized	O
Carmack	O
's	O
programming	O
feat	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
scrolling	O
technique	O
did	O
not	O
meet	O
Softdisk	O
's	O
coding	O
guidelines	O
as	O
it	O
needed	O
at	O
least	O
a	O
16-color	O
EGA	B-Device
graphics	I-Device
processor	O
,	O
and	O
the	O
programmers	O
in	O
the	O
office	O
who	O
did	O
not	O
work	O
on	O
games	O
were	O
not	O
as	O
impressed	O
as	O
Romero	O
.	O
</s>
<s>
The	O
manager	O
of	O
the	O
team	O
,	O
fellow	O
programmer	O
Jay	O
Wilbur	O
,	O
recommended	O
that	O
they	O
take	O
the	O
demo	O
to	O
Nintendo	O
itself	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
group	O
then	O
spent	O
the	O
next	O
72	O
hours	O
working	O
non-stop	O
on	O
the	O
demo	O
,	O
which	O
copied	O
Super	B-Application
Mario	I-Application
Bros	I-Application
.	I-Application
3	I-Application
with	O
some	O
shortcuts	O
taken	O
in	O
the	O
artwork	O
,	O
sound	O
,	O
and	O
level	O
design	O
,	O
and	O
a	O
title	O
screen	O
that	O
credited	O
the	O
game	O
to	O
the	O
programmers	O
under	O
the	O
name	O
Ideas	O
from	O
the	O
Deep	O
,	O
a	O
name	O
Romero	O
had	O
used	O
for	O
some	O
prior	O
Softdisk	O
projects	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
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>
He	O
wanted	O
to	O
convince	O
Romero	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
in	O
which	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
sent	O
Miller	O
the	O
Mario	B-Application
demo	O
,	O
and	O
the	O
two	O
agreed	O
that	O
Ideas	O
from	O
the	O
Deep	O
would	O
create	O
a	O
new	O
game	O
for	O
Apogee	O
.	O
</s>
<s>
The	O
game	O
was	O
planned	O
to	O
be	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>
Ideas	O
from	O
the	O
Deep	O
convened	O
to	O
come	O
up	O
with	O
the	O
design	O
for	O
the	O
game	O
,	O
and	O
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
</s>
<s>
When	O
he	O
read	O
out	O
the	O
summary	O
in	O
an	O
over-dramatic	O
voice	O
to	O
the	O
group	O
,	O
they	O
laughed	O
and	O
applauded	O
,	O
and	O
the	O
group	O
agreed	O
to	O
begin	O
work	O
on	O
Commander	B-Application
Keen	I-Application
in	O
the	O
Invasion	B-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
,	O
who	O
referred	O
to	O
themselves	O
as	O
the	O
"	O
IFD	O
guys	O
"	O
,	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
making	O
Gamer	O
's	O
Edge	O
games	O
during	O
the	O
day	O
while	O
working	O
on	O
Commander	B-Application
Keen	I-Application
at	O
night	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
.	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
a	O
"	O
Galactic	O
Alphabet	O
"	O
in	O
which	O
signs	O
in	O
the	O
game	O
were	O
written	O
,	O
which	O
if	O
deciphered	O
by	O
the	O
players	O
revealed	O
hidden	O
messages	O
,	O
jokes	O
,	O
and	O
instructions	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
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
as	O
well	O
as	O
sending	O
the	O
team	O
US$100	O
checks	O
every	O
week	O
labelled	O
"	O
pizza	O
bonus	O
"	O
after	O
one	O
of	O
the	O
game	O
's	O
food	O
items	O
to	O
keep	O
them	O
motivated	O
.	O
</s>
<s>
Commander	B-Application
Keen	I-Application
was	O
an	O
immediate	O
hit	O
for	O
Apogee	O
:	O
the	O
company	O
's	O
previous	O
sales	O
levels	O
had	O
been	O
around	O
US$	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>
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	O
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	O
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
including	O
the	O
Vorticon	B-Application
trilogy	O
,	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
though	O
still	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>
In	O
the	O
2017	O
History	O
of	O
Digital	O
Games	O
,	O
author	O
Andrew	O
Williams	O
claims	O
that	O
Vorticons	B-Application
"	O
signaled	O
a	O
new	O
direction	O
for	O
computer	O
games	O
in	O
general	O
"	O
,	O
as	O
well	O
as	O
setting	O
a	O
tone	O
of	O
gameplay	O
mechanics	O
for	O
future	O
id	O
games	O
,	O
by	O
introducing	O
a	O
sense	O
of	O
"	O
effortless	O
movement	O
"	O
as	O
players	O
explored	O
through	O
large	O
open	O
spaces	O
instead	O
of	O
disconnected	O
screens	O
like	O
prior	O
platforming	O
computer	O
games	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>
Id	O
Software	O
also	O
produced	O
several	O
more	O
games	O
in	O
the	O
Commander	B-Application
Keen	I-Application
series	O
;	O
the	O
first	O
of	O
these	O
,	O
Commander	B-Application
Keen	I-Application
in	I-Application
Keen	I-Application
Dreams	I-Application
,	O
was	O
published	O
in	O
1991	O
through	O
their	O
agreement	O
with	O
Softdisk	O
.	O
</s>
<s>
Commander	B-Application
Keen	I-Application
in	I-Application
Goodbye	I-Application
,	I-Application
Galaxy	I-Application
,	O
composed	O
of	O
the	O
episodes	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
was	O
published	O
through	O
Apogee	O
in	O
December	O
1991	O
,	O
and	O
the	O
final	O
id-developed	O
Keen	O
game	O
,	O
Commander	B-Application
Keen	I-Application
in	I-Application
Aliens	I-Application
Ate	I-Application
My	I-Application
Babysitter	I-Application
,	O
was	O
published	O
through	O
FormGen	O
around	O
the	O
same	O
time	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
but	O
was	O
cancelled	O
after	O
the	O
success	O
of	O
id	O
's	O
Wolfenstein	B-Application
3D	I-Application
and	O
development	O
focus	O
on	O
Doom	B-Application
.	O
</s>
<s>
A	O
final	O
Keen	O
game	O
,	O
Commander	B-Application
Keen	I-Application
,	O
was	O
developed	O
for	O
the	O
Game	B-Device
Boy	I-Device
Color	I-Device
in	O
2001	O
by	O
David	O
A	O
.	O
Palmer	O
Productions	O
in	O
association	O
with	O
id	O
Software	O
,	O
and	O
published	O
by	O
Activision	O
.	O
</s>
<s>
The	O
original	O
trilogy	O
has	O
been	O
released	O
as	O
part	O
of	O
several	O
collections	O
since	O
its	O
first	O
release	O
:	O
the	O
id	O
Anthology	O
compilation	O
in	O
1996	O
,	O
a	O
compilation	O
release	O
by	O
Apogee	O
in	O
1998	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
a	O
similar	O
compilation	O
in	O
2001	O
by	O
3D	O
Realms	O
titled	O
Commander	B-Application
Keen	I-Application
Combo	O
CD	O
,	O
and	O
the	O
3D	O
Realms	O
Anthology	O
in	O
2014	O
.	O
</s>
<s>
They	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
a	O
part	O
of	O
the	O
Commander	B-Application
Keen	I-Application
Complete	O
Pack	O
.	O
</s>
<s>
According	O
to	O
Steam	B-Application
Spy	O
,	O
as	O
of	O
2017	O
over	O
200,000	O
copies	O
are	O
registered	O
through	O
Steam	B-Application
.	O
</s>
