<s>
Zork	B-Application
is	I-Application
a	O
text-based	O
adventure	B-Application
game	O
first	O
released	O
in	O
1977	O
by	O
developers	O
Tim	O
Anderson	O
,	O
Marc	O
Blank	O
,	O
Bruce	O
Daniels	O
,	O
and	O
Dave	O
Lebling	O
for	O
the	O
PDP-10	B-Device
mainframe	B-Architecture
computer	I-Architecture
.	O
</s>
<s>
The	O
original	O
developers	O
and	O
others	O
,	O
as	O
the	O
company	O
Infocom	O
,	O
expanded	O
and	O
split	O
the	O
game	O
into	O
three	O
titlesZorkI	O
:	O
The	B-Application
Great	I-Application
Underground	I-Application
Empire	I-Application
,	O
ZorkII	O
:	O
The	O
Wizard	O
of	O
Frobozz	B-Application
,	O
and	O
ZorkIII	O
:	O
The	O
Dungeon	O
Masterwhich	O
were	O
released	O
commercially	O
for	O
a	O
range	O
of	O
personal	B-Device
computers	I-Device
beginning	O
in	O
1980	O
.	O
</s>
<s>
In	O
Zork	B-Application
,	O
the	O
player	O
explores	O
the	O
abandoned	O
Great	B-Application
Underground	I-Application
Empire	I-Application
in	O
search	O
of	O
treasure	O
.	O
</s>
<s>
The	O
player	O
moves	O
between	O
the	O
game	O
's	O
hundreds	O
of	O
locations	O
and	O
interacts	O
with	O
objects	O
by	O
typing	O
commands	O
in	O
natural	B-Language
language	I-Language
that	O
the	O
game	O
interprets	O
.	O
</s>
<s>
The	O
original	O
game	O
,	O
developed	O
between	O
1977	O
and	O
1979	O
at	O
the	O
Massachusetts	O
Institute	O
of	O
Technology	O
(	O
MIT	O
)	O
,	O
was	O
inspired	O
by	O
Colossal	B-Application
Cave	I-Application
Adventure	I-Application
(	O
1976	O
)	O
,	O
the	O
first	O
well-known	O
example	O
of	O
interactive	O
fiction	O
and	O
the	O
first	O
well-known	O
adventure	B-Application
game	O
.	O
</s>
<s>
The	O
developers	O
wanted	O
to	O
make	O
a	O
similar	O
game	O
that	O
was	O
able	O
to	O
understand	O
more	O
complicated	O
sentences	O
than	O
Adventure	B-Application
two-word	O
commands	O
.	O
</s>
<s>
Blank	O
and	O
Joel	O
Berez	O
created	O
a	O
way	O
to	O
run	O
a	O
smaller	O
portion	O
of	O
Zork	B-Application
on	O
several	O
brands	O
of	O
microcomputer	B-Architecture
,	O
letting	O
them	O
commercialize	O
the	O
game	O
as	O
Infocom	O
's	O
first	O
products	O
.	O
</s>
<s>
Zork	B-Application
was	O
a	O
massive	O
success	O
for	O
Infocom	O
,	O
with	O
sales	O
increasing	O
for	O
years	O
as	O
the	O
market	O
for	O
personal	B-Device
computers	I-Device
expanded	O
.	O
</s>
<s>
Infocom	O
was	O
purchased	O
by	O
Activision	O
in	O
1986	O
,	O
leading	O
to	O
new	O
Zork	B-Application
games	O
beginning	O
in	O
1987	O
,	O
as	O
well	O
as	O
a	O
series	O
of	O
books	O
.	O
</s>
<s>
Reviews	O
of	O
the	O
episodes	O
were	O
very	O
positive	O
,	O
several	O
reviewers	O
calling	O
Zork	B-Application
the	O
best	O
adventure	B-Application
game	O
to	O
date	O
.	O
</s>
<s>
Later	O
historians	O
have	O
noted	O
the	O
game	O
as	O
foundational	O
to	O
the	O
adventure	B-Application
game	O
genre	O
,	O
as	O
well	O
as	O
influencing	O
the	O
MUD	B-Application
and	O
massively	B-Protocol
multiplayer	I-Protocol
online	I-Protocol
role-playing	I-Protocol
game	I-Protocol
genres	O
.	O
</s>
<s>
In	O
2007	O
,	O
Zork	B-Application
was	O
included	O
in	O
the	O
game	O
canon	O
by	O
the	O
Library	O
of	O
Congress	O
as	O
one	O
of	O
the	O
ten	O
most	O
important	O
video	O
games	O
in	O
history	O
.	O
</s>
<s>
Zork	B-Application
is	I-Application
a	O
text-based	O
adventure	B-Application
game	O
wherein	O
the	O
player	O
explores	O
the	O
ruins	O
of	O
the	B-Application
Great	I-Application
Underground	I-Application
Empire	I-Application
.	O
</s>
<s>
The	O
program	O
's	O
replies	O
are	O
typically	O
in	O
a	O
sarcastic	O
,	O
conversational	O
tone	O
,	O
much	O
as	O
a	O
Game	B-Device
Master	I-Device
would	O
use	O
in	O
leading	O
players	O
in	O
a	O
tabletop	O
role-playing	O
game	O
.	O
</s>
<s>
The	O
original	O
1977	O
version	O
of	O
the	O
game	O
was	O
a	O
single	O
release	O
,	O
Zork	B-Application
.	O
</s>
<s>
Much	O
of	O
the	O
game	O
world	O
is	O
composed	O
of	O
puzzles	O
that	O
must	O
eventually	O
be	O
solved	O
,	O
such	O
as	O
a	O
set	O
of	O
buttons	O
on	O
a	O
dam	O
or	O
a	O
maze	B-Application
to	O
be	O
traversed	O
.	O
</s>
<s>
Zork	B-Application
does	O
not	O
follow	O
a	O
linear	O
storyline	O
.	O
</s>
<s>
Long	O
before	O
the	O
time	O
the	O
game	O
is	O
set	O
in	O
,	O
the	O
Quendor	B-Application
empire	O
,	O
having	O
conquered	O
everywhere	O
above	O
ground	O
,	O
built	O
a	O
massive	O
cave	O
complex	O
to	O
expand	O
.	O
</s>
<s>
Two	O
hundred	O
years	O
later	O
,	O
the	O
ruler	O
Lord	O
Dimwit	O
Flathead	O
renamed	O
the	O
empire	O
to	O
the	B-Application
Great	I-Application
Underground	I-Application
Empire	I-Application
and	O
spent	O
his	O
reign	O
building	O
massive	O
,	O
largely	O
pointless	O
projects	O
such	O
as	O
an	O
underground	O
dam	O
and	O
the	O
royal	O
museum	O
.	O
</s>
<s>
The	O
abandoned	O
empire	O
is	O
the	O
setting	O
of	O
the	O
three	O
episodes	O
of	O
Zork	B-Application
.	O
</s>
<s>
Zork	B-Application
I	I-Application
begins	O
with	O
the	O
unnamed	O
player	O
character	O
near	O
a	O
white	B-Application
house	I-Application
in	O
a	O
small	O
,	O
self-contained	O
area	O
;	O
most	O
of	O
the	O
game	O
occurs	O
underground	O
,	O
as	O
do	O
the	O
subsequent	O
episodes	O
.	O
</s>
<s>
In	O
ZorkII	O
the	O
player	O
learns	O
of	O
the	O
Flatheads	O
,	O
and	O
meets	O
the	O
Wizard	O
of	O
Frobozz	B-Application
,	O
who	O
was	O
once	O
a	O
respected	O
enchanter	B-Application
but	O
was	O
exiled	O
by	O
Lord	O
Dimwit	O
Flathead	O
when	O
his	O
powers	O
began	O
to	O
fade	O
.	O
</s>
<s>
In	O
ZorkIII	O
the	O
player	O
character	O
gathers	O
the	O
garb	O
of	O
the	O
Dungeon	B-Device
Master	I-Device
to	O
become	O
his	O
successor	O
.	O
</s>
<s>
Once	O
the	O
player	O
has	O
all	O
the	O
items	O
,	O
they	O
must	O
feed	O
an	O
elderly	O
man	O
,	O
who	O
reveals	O
himself	O
as	O
the	O
Dungeon	B-Device
Master	I-Device
and	O
shows	O
them	O
the	O
doorway	O
leading	O
to	O
the	O
final	O
hallway	O
.	O
</s>
<s>
After	O
the	O
player	O
solves	O
the	O
final	O
puzzles	O
,	O
the	O
Dungeon	B-Device
Master	I-Device
appears	O
and	O
transforms	O
the	O
player	O
to	O
look	O
like	O
himself	O
,	O
signifying	O
the	O
player	O
's	O
succession	O
to	O
his	O
position	O
.	O
</s>
<s>
Tim	O
Anderson	O
,	O
Marc	O
Blank	O
,	O
Bruce	O
Daniels	O
,	O
and	O
Dave	O
Lebling	O
began	O
developing	O
Zork	B-Application
in	O
May	O
1977	O
.	O
</s>
<s>
Their	O
work	O
was	O
inspired	O
by	O
Colossal	B-Application
Cave	I-Application
Adventure	I-Application
,	O
a	O
text-based	O
game	O
that	O
is	O
the	O
first	O
well-known	O
example	O
of	O
interactive	O
fiction	O
and	O
the	O
first	O
well-known	O
adventure	B-Application
game	O
.	O
</s>
<s>
Adventure	B-Application
was	O
immensely	O
popular	O
among	O
the	O
small	O
population	O
of	O
computer	O
users	O
of	O
the	O
time	O
and	O
a	O
big	O
hit	O
at	O
MIT	O
in	O
early	O
1977	O
.	O
</s>
<s>
The	O
four	O
programmers	O
began	O
to	O
design	O
a	O
game	O
that	O
would	O
be	O
a	O
"	O
better	O
"	O
text	O
adventure	B-Application
game	O
,	O
with	O
inputs	O
more	O
complex	O
than	O
Adventures	B-Application
two-word	O
commands	O
and	O
puzzles	O
less	O
obtuse	O
.	O
</s>
<s>
They	O
believed	O
that	O
their	O
division	O
's	O
MDL	B-Language
programming	I-Language
language	I-Language
would	O
be	O
better	O
suited	O
for	O
processing	O
complex	O
text	O
inputs	O
than	O
the	O
Fortran	B-Application
code	O
used	O
in	O
Adventure	B-Application
.	O
</s>
<s>
The	O
group	O
was	O
familiar	O
with	O
creating	O
video	O
games	O
:	O
Blank	O
and	O
Anderson	O
had	O
worked	O
on	O
a	O
multiplayer	O
trivia	O
game	O
called	O
Trivia	O
(	O
1976	O
)	O
,	O
and	O
Lebling	O
was	O
heavily	O
involved	O
with	O
Maze	B-Application
(	O
1973	O
)	O
,	O
a	O
multiplayer	O
first-person	O
shooter	O
and	O
the	O
first	O
3D	O
first-person	O
game	O
ever	O
made	O
.	O
</s>
<s>
Lebling	O
first	O
created	O
a	O
natural	B-Language
language	I-Language
input	I-Language
system	O
,	O
or	O
parser	O
,	O
that	O
could	O
process	O
typed	O
two-word	O
instructions	O
.	O
</s>
<s>
Zork	B-Application
prototype	O
was	O
built	O
for	O
the	O
Digital	O
Equipment	O
Corporation	O
(	O
DEC	O
)	O
PDP-10	B-Device
mainframe	B-Architecture
computer	I-Architecture
,	O
the	O
only	O
system	O
that	O
supported	O
their	O
programming	O
language	O
.	O
</s>
<s>
While	O
Lebling	O
took	O
a	O
two-week	O
vacation	O
,	O
Anderson	O
,	O
Blank	O
,	O
and	O
Daniels	O
designed	O
an	O
adventure	B-Application
game	O
concept	O
,	O
which	O
Anderson	O
and	O
Blank	O
then	O
developed	O
as	O
an	O
early	O
version	O
of	O
Zork	B-Application
.	O
</s>
<s>
According	O
to	O
Anderson	O
,	O
"	O
it	O
took	O
time	O
for	O
people	O
to	O
learn	O
how	O
to	O
write	O
good	O
problems	O
"	O
,	O
and	O
Lebling	O
's	O
first	O
,	O
uncomplex	O
parser	O
was	O
only	O
"	O
almost	O
as	O
smart	O
as	O
Adventures	B-Application
"	O
.	O
</s>
<s>
The	O
game	O
was	O
unnamed	O
,	O
but	O
the	O
group	O
had	O
a	O
habit	O
of	O
naming	O
their	O
programs	O
"	O
zork	B-Application
"	O
until	O
they	O
were	O
completed	O
,	O
a	O
term	O
in	O
the	O
MIT	O
community	O
for	O
an	O
in-development	O
program	O
.	O
</s>
<s>
Lebling	O
contends	O
that	O
Adventure	B-Application
was	O
one	O
of	O
Zorks	B-Application
only	O
influences	O
,	O
as	O
there	O
were	O
few	O
other	O
games	O
to	O
emulate	O
at	O
the	O
time	O
.	O
</s>
<s>
He	O
also	O
thought	O
of	O
the	O
parser	O
and	O
associated	O
text	O
responses	O
as	O
taking	O
on	O
the	O
role	O
of	O
the	O
Dungeon	B-Device
Master	I-Device
from	O
a	O
Dungeons	O
&	O
Dragons	O
game	O
,	O
trying	O
to	O
lead	O
the	O
player	O
through	O
a	O
story	O
solely	O
by	O
describing	O
it	O
;	O
this	O
had	O
also	O
been	O
the	O
idea	O
behind	O
the	O
parser	O
in	O
Adventure	B-Application
.	O
</s>
<s>
The	O
developers	O
did	O
not	O
announce	O
their	O
game	O
while	O
it	O
was	O
in	O
development	O
,	O
but	O
a	O
lack	O
of	O
security	O
on	O
the	O
MIT	O
systems	O
meant	O
that	O
anyone	O
who	O
could	O
access	O
the	O
PDP-10	B-Device
computer	O
over	O
the	O
ARPANET	O
could	O
see	O
what	O
programs	O
were	O
being	O
run	O
.	O
</s>
<s>
They	O
found	O
the	O
new	O
"	O
Zork	B-Application
"	O
adventure	B-Application
game	O
and	O
spread	O
word	O
of	O
it	O
under	O
that	O
name	O
.	O
</s>
<s>
This	O
communitydozens	O
or	O
possibly	O
hundreds	O
of	O
players	O
,	O
according	O
to	O
Leblinginteracted	O
with	O
the	O
developers	O
as	O
they	O
created	O
the	O
game	O
,	O
playtesting	O
additions	O
and	O
submitting	O
bug	B-Error_Name
reports	O
.	O
</s>
<s>
By	O
the	O
end	O
of	O
June	O
,	O
the	O
game	O
was	O
approximately	O
half	O
the	O
size	O
of	O
the	O
final	O
Zork	B-Application
,	O
and	O
had	O
a	O
substantial	O
community	O
of	O
players	O
for	O
the	O
time	O
.	O
</s>
<s>
Following	O
user	O
requests	O
,	O
they	O
also	O
added	O
the	O
ability	O
for	O
the	O
game	O
to	O
run	O
on	O
PDP-10	B-Device
computers	O
running	O
different	O
operating	O
systemsTENEX	O
and	O
TOPS-20which	O
were	O
much	O
more	O
popular	O
than	O
the	O
Incompatible	B-Application
Timesharing	I-Application
System	I-Application
operating	O
system	O
the	O
MIT	O
computer	O
used	O
.	O
</s>
<s>
Around	O
this	O
time	O
,	O
community	O
member	O
Ted	O
Hess	O
at	O
DEC	O
decoded	O
the	O
protections	B-Application
the	O
group	O
had	O
made	O
for	O
the	O
source	O
code	O
,	O
and	O
another	O
DEC	O
employee	O
,	O
Bob	O
Supnik	O
,	O
created	O
a	O
port	O
of	O
the	O
game	O
to	O
Fortran	B-Application
.	O
</s>
<s>
This	O
port	O
,	O
released	O
in	O
March	O
1978	O
,	O
opened	O
the	O
game	O
to	O
a	O
wider	O
set	O
of	O
players	O
without	O
access	O
to	O
a	O
PDP-10	B-Device
mainframe	B-Architecture
.	O
</s>
<s>
At	O
the	O
time	O
,	O
the	O
team	O
had	O
decided	O
to	O
give	O
the	O
game	O
an	O
actual	O
name	O
besides	O
"	O
zork	B-Application
"	O
,	O
and	O
chose	O
Dungeon	O
.	O
</s>
<s>
This	O
name	O
was	O
used	O
for	O
the	O
Fortran	B-Application
version	O
,	O
which	O
was	O
spread	O
through	O
the	O
DEC	O
users	O
group	O
as	O
one	O
of	O
its	O
most	O
popular	O
pieces	O
of	O
software	O
.	O
</s>
<s>
Over	O
the	O
course	O
of	O
1978	O
,	O
the	O
team	O
added	O
the	O
bank	O
and	O
Royal	O
Zork	B-Application
Puzzle	O
Museum	O
sections	O
,	O
along	O
with	O
some	O
puzzles	O
and	O
ideas	O
suggested	O
by	O
players	O
.	O
</s>
<s>
The	O
last	O
puzzle	O
was	O
added	O
in	O
February	O
1979	O
,	O
though	O
the	O
team	O
continued	O
to	O
release	O
bug	B-Error_Name
fix	O
updates	O
until	O
the	O
final	O
update	O
in	O
January	O
1981	O
.	O
</s>
<s>
Anderson	O
attributes	O
this	O
to	O
the	O
team	O
running	O
out	O
of	O
ideas	O
and	O
time	O
,	O
and	O
having	O
run	O
out	O
of	O
space	O
in	O
the	O
one	O
megabyte	O
of	O
memory	B-General_Concept
allocated	O
for	O
the	O
game	O
.	O
</s>
<s>
No	O
specific	O
projects	O
were	O
initially	O
agreed	O
upon	O
and	O
Infocom	O
had	O
no	O
paid	O
employees	O
,	O
but	O
discussions	O
were	O
focused	O
on	O
developing	O
software	O
for	O
smaller	B-Architecture
mainframe	I-Architecture
computers	I-Architecture
.	O
</s>
<s>
Blank	O
and	O
Joel	O
Berez	O
came	O
up	O
with	O
a	O
plan	O
to	O
make	O
Zork	B-Application
work	O
on	O
personal	O
microcomputers	B-Architecture
,	O
which	O
were	O
then	O
beginning	O
to	O
become	O
popular	O
and	O
which	O
would	O
greatly	O
expand	O
the	O
audience	O
for	O
the	O
game	O
.	O
</s>
<s>
Although	O
microcomputers	B-Architecture
had	O
very	O
limited	O
memory	B-General_Concept
space	O
compared	O
to	O
mainframe	B-Architecture
computers	I-Architecture
,	O
they	O
felt	O
the	O
project	O
might	O
be	O
viable	O
using	O
floppy	B-Device
disks	I-Device
and	O
a	O
custom	O
programming	O
language	O
if	O
the	O
game	O
was	O
cut	O
into	O
two	O
pieces	O
.	O
</s>
<s>
They	O
ported	O
the	O
game	O
to	O
a	O
new	O
Zork	B-Application
Implementation	O
Language	O
(	O
ZIL	O
)	O
,	O
which	O
would	O
then	O
be	O
run	O
on	O
a	O
standardized	O
"	O
Z-machine	O
"	O
software-based	O
computer	O
.	O
</s>
<s>
For	O
each	O
type	O
of	O
microcomputer	B-Architecture
they	O
wanted	O
to	O
release	O
Zork	B-Application
or	O
other	O
ZIL-based	O
games	O
on	O
,	O
they	O
could	O
write	O
an	O
interpreter	O
program	O
that	O
could	O
run	O
the	O
Z-Machine	O
instead	O
of	O
rewriting	O
each	O
game	O
.	O
</s>
<s>
Lebling	O
divided	O
Zork	B-Application
in	O
half	O
to	O
create	O
standalone	O
episodes	O
,	O
modifying	O
the	O
game	O
's	O
layout	O
to	O
improve	O
its	O
flow	O
and	O
disconnecting	O
locations	O
now	O
in	O
separate	O
episodes	O
.	O
</s>
<s>
The	O
core	O
game	O
was	O
complete	O
,	O
but	O
it	O
had	O
been	O
run	O
only	O
on	O
DECSYSTEM-20	B-Device
and	O
PDP-11	B-Device
mainframe	B-Architecture
computers	I-Architecture
.	O
</s>
<s>
Infocom	O
purchased	O
a	O
TRS-80	B-Device
personal	B-Device
computer	I-Device
early	O
in	O
1980	O
,	O
which	O
could	O
run	O
the	O
game	O
after	O
Blank	O
and	O
Scott	O
Cutler	O
created	O
an	O
interpreter	O
program	O
.	O
</s>
<s>
Infocom	O
began	O
preparing	O
to	O
release	O
the	O
first	O
section	O
under	O
the	O
title	O
Zork	B-Application
:	O
The	O
Great	O
Underground	O
EmpirePartI	O
.	O
</s>
<s>
Berez	O
approached	O
Microsoft	O
,	O
who	O
declined	O
based	O
on	O
the	O
game	O
competing	O
with	O
Microsoft	B-Application
Adventure	I-Application
(	O
1979	O
)	O
,	O
their	O
version	O
of	O
Adventure	B-Application
.	O
</s>
<s>
Microsoft	O
CEO	O
Bill	O
Gates	O
was	O
a	O
fan	O
of	O
Zork	B-Application
,	O
but	O
by	O
the	O
time	O
he	O
heard	O
of	O
the	O
proposal	O
,	O
Infocom	O
was	O
in	O
negotiations	O
with	O
another	O
publisher	O
,	O
Personal	O
Software	O
,	O
one	O
of	O
the	O
first	O
professional	O
software	O
publishing	O
companies	O
.	O
</s>
<s>
Zork	B-Application
:	I-Application
The	I-Application
Great	I-Application
Underground	I-Application
Empire	I-Application
,	O
also	O
known	O
as	O
ZorkI	O
or	O
just	O
Zork	B-Application
,	O
was	O
published	O
for	O
the	O
TRS-80	B-Device
in	O
December	O
1980	O
.	O
</s>
<s>
Since	O
Personal	O
Software	O
declined	O
to	O
publish	O
the	O
1979	O
PDP-11	B-Device
version	O
of	O
the	O
game	O
,	O
Infocom	O
sold	O
some	O
copies	O
earlier	O
in	O
the	O
year	O
after	O
announcing	O
to	O
PDP-11	B-Device
user	O
groups	O
.	O
</s>
<s>
Lebling	O
recalled	O
about	O
twenty	O
floppy	B-Device
disk	I-Device
copies	O
sold	O
directly	O
with	O
Anderson	O
's	O
typewritten	O
manual	O
.	O
</s>
<s>
By	O
the	O
end	O
of	O
1980	O
,	O
an	O
Apple	B-Device
II	I-Device
version	O
of	O
ZorkI	O
was	O
completed	O
and	O
sold	O
through	O
Personal	O
Software	O
.	O
</s>
<s>
Infocom	O
began	O
receiving	O
requests	O
for	O
hints	O
and	O
maps	O
as	O
predicted	O
,	O
and	O
Berez	O
began	O
handling	O
map	O
and	O
poster	O
orders	O
while	O
Dornbrook	O
wrote	O
customized	O
hints	O
for	O
players	O
;	O
in	O
September	O
1981	O
he	O
founded	O
the	O
Zork	B-Application
Users	O
Group	O
as	O
a	O
separate	O
company	O
to	O
handle	O
all	O
mail	O
order	O
sales	O
and	O
hint	O
requests	O
.	O
</s>
<s>
Meanwhile	O
Lebling	O
worked	O
on	O
converting	O
the	O
second	O
half	O
of	O
Zork	B-Application
into	O
ZorkII	O
,	O
but	O
in	O
the	O
process	O
thought	O
up	O
several	O
new	O
puzzles	O
for	O
the	O
game	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
the	O
game	O
was	O
split	O
again	O
into	O
ZorkII	O
:	O
The	O
Wizard	O
of	O
Frobozz	B-Application
and	O
ZorkIII	O
:	O
The	O
Dungeon	B-Device
Master	I-Device
.	O
</s>
<s>
According	O
to	O
Lebling	O
,	O
splitting	O
the	O
game	O
into	O
episodes	O
led	O
to	O
different	O
atmospheres	O
:	O
ZorkI	O
was	O
focused	O
on	O
exploration	O
and	O
Adventure-style	O
gameplay	O
,	O
II	O
had	O
more	O
of	O
a	O
focus	O
on	O
plot	O
and	O
added	O
magic	O
spells	O
to	O
the	O
base	O
game	O
,	O
and	O
III	O
was	O
less	O
straightforward	O
,	O
with	O
time-sensitive	O
aspects	O
.	O
</s>
<s>
Zork	B-Application
II	I-Application
was	O
offered	O
to	O
Personal	O
Software	O
in	O
April	O
1981	O
and	O
the	O
contract	O
was	O
signed	O
in	O
June	O
,	O
but	O
Infocom	O
grew	O
wary	O
of	O
continuing	O
this	O
relationship	O
.	O
</s>
<s>
The	O
Infocom	O
team	O
felt	O
that	O
Personal	O
Software	O
was	O
not	O
advertising	O
ZorkI	O
very	O
strongly	O
,	O
and	O
did	O
not	O
seem	O
excited	O
about	O
Infocom	O
's	O
plans	O
for	O
ZorkIII	O
and	O
other	O
planned	O
text	O
adventure	B-Application
games	O
such	O
as	O
Deadline	O
and	O
Starcross	B-Application
.	O
</s>
<s>
Personal	O
Software	O
soon	O
stopped	O
publishing	O
entertainment	O
software	O
altogether	O
and	O
rebranded	O
as	O
VisiCorp	O
in	O
1982	O
to	O
align	O
with	O
its	O
VisiCalc	B-Application
spreadsheet	O
software	O
.	O
</s>
<s>
Infocom	O
developed	O
interpreters	O
for	O
the	O
Commodore	O
64	O
,	O
the	O
Atari	B-Device
8-bit	I-Device
family	I-Device
of	O
computers	O
,	O
CP/M	B-Application
systems	O
,	O
and	O
the	O
IBM	B-Device
Personal	I-Device
Computer	I-Device
,	O
and	O
released	O
the	O
episodes	O
of	O
Zork	B-Application
for	O
them	O
as	O
well	O
in	O
1982	O
.	O
</s>
<s>
In	O
its	O
first	O
nine	O
months	O
Personal	O
Software	O
sold	O
7,500	O
copies	O
for	O
the	O
TRS-80	B-Device
and	O
AppleII	O
.	O
</s>
<s>
Sales	O
ballooned	O
as	O
Infocom	O
began	O
self-publishing	O
the	O
trilogy	O
and	O
the	O
personal	B-Device
computer	I-Device
market	O
expanded	O
.	O
</s>
<s>
The	O
second	O
and	O
third	O
parts	O
of	O
Zork	B-Application
also	O
sold	O
well	O
,	O
though	O
not	O
as	O
highly	O
as	O
the	O
first	O
:	O
more	O
than	O
170,000	O
ZorkII	O
and	O
130,000	O
ZorkIII	O
copies	O
sold	O
by	O
1986	O
.	O
</s>
<s>
Combined	O
,	O
they	O
sold	O
more	O
than	O
250,000	O
copies	O
by	O
1984	O
,	O
and	O
more	O
than	O
680,000	O
copies	O
through	O
1986	O
,	O
including	O
the	O
1986	O
Zork	B-Application
Trilogy	I-Application
compilation	O
release	O
.	O
</s>
<s>
Between	O
1982	O
and	O
1986	O
,	O
the	O
Zork	B-Application
trilogy	I-Application
composed	O
more	O
than	O
one-third	O
of	O
Infocom	O
's	O
two	O
million	O
total	O
game	O
sales	O
.	O
</s>
<s>
Activision	O
purchased	O
Infocom	O
in	O
1986	O
and	O
reported	O
that	O
the	O
three	O
Zork	B-Application
games	O
and	O
trilogy	O
compilation	O
sold	O
another	O
80,000	O
copies	O
by	O
early	O
1989	O
.	O
</s>
<s>
The	O
episodes	O
of	O
Zork	B-Application
were	O
highly	O
praised	O
in	O
contemporaneous	O
reviews	O
.	O
</s>
<s>
Reviewers	O
for	O
Softalk	O
and	O
The	O
Space	O
Gamer	O
enjoyed	O
how	O
the	O
parser	O
let	O
them	O
input	O
more	O
complex	O
sentences	O
than	O
did	O
earlier	O
games	O
,	O
the	O
Softalk	O
review	O
noting	O
that	O
every	O
other	O
game	O
since	O
Adventure	B-Application
had	O
limited	O
the	O
player	O
to	O
two-word	O
phrases	O
,	O
though	O
they	O
also	O
thought	O
players	O
would	O
largely	O
stick	O
with	O
clearer	O
two-word	O
commands	O
.	O
</s>
<s>
80	O
Micro	O
wondered	O
whether	O
Zork	B-Application
could	O
ever	O
be	O
completed	O
because	O
of	O
how	O
much	O
the	O
parser	O
let	O
the	O
player	O
do	O
.	O
</s>
<s>
Byte	O
concluded	O
that	O
"	O
no	O
single	O
advance	O
in	O
the	O
science	O
of	O
Adventure	B-Application
has	O
been	O
as	O
bold	O
and	O
exciting	O
"	O
as	O
Zork	B-Application
,	O
a	O
sentiment	O
echoed	O
by	O
Softalk	O
.	O
</s>
<s>
In	O
the	O
years	O
after	O
its	O
release	O
,	O
ZorkI	O
received	O
more	O
reviews	O
praising	O
the	O
game	O
in	O
relation	O
to	O
Adventure	B-Application
and	O
the	O
genre	O
.	O
</s>
<s>
Jerry	O
Pournelle	O
recommended	O
the	O
game	O
in	O
his	O
long-running	O
Byte	O
column	O
,	O
stating	O
in	O
1983	O
that	O
"	O
if	O
you	O
liked	O
Adventure	B-Application
and	O
wanted	O
more	O
...	O
</s>
<s>
I	O
guarantee	O
you	O
'll	O
love	O
Zork	B-Application
"	O
.	O
</s>
<s>
Computer	O
Gaming	O
World	O
in	O
1982	O
,	O
PC	O
Magazine	O
in	O
1982	O
,	O
and	O
SoftSide	O
in	O
1983	O
all	O
recommended	O
it	O
as	O
a	O
"	O
must-have	O
"	O
for	O
anyone	O
interested	O
in	O
fantasy	O
or	O
adventure	B-Application
games	O
.	O
</s>
<s>
Family	O
Computing	O
,	O
in	O
late	O
1983	O
,	O
proclaimed	O
it	O
a	O
classic	O
of	O
the	O
genre	O
and	O
the	O
game	O
that	O
made	O
the	O
adventure	B-Application
genre	O
more	O
than	O
a	O
novelty	O
.	O
</s>
<s>
Reviewers	O
similarly	O
praised	O
Zork	B-Application
second	O
and	O
third	O
episodes	O
.	O
</s>
<s>
A	O
reviewer	O
for	O
Softalk	O
said	O
it	O
broke	O
away	O
from	O
both	O
the	O
first	O
episode	O
and	O
Adventure	B-Application
to	O
be	O
"	O
fresh	O
and	O
interesting	O
"	O
.	O
</s>
<s>
K-Power	O
concluded	O
that	O
ZorkIII	O
was	O
"	O
the	O
most	O
intelligent	O
text	O
game	O
for	O
a	O
microcomputer	B-Architecture
that	O
we	O
've	O
ever	O
seen	O
"	O
.	O
</s>
<s>
Commodore	O
Magazine	O
,	O
in	O
June	O
1983	O
,	O
described	O
the	O
combined	O
trilogy	O
as	O
the	O
most	O
popular	O
adventure	B-Application
game	O
,	O
as	O
well	O
as	O
the	O
best	O
.	O
</s>
<s>
The	O
Addison-Wesley	O
Book	O
of	O
Atari	O
Software	O
1984	O
gave	O
all	O
three	O
parts	O
of	O
Zork	B-Application
an	O
overall	O
A+	O
rating	O
.	O
</s>
<s>
It	O
called	O
ZorkI	O
"	O
the	O
definitive	O
adventure	B-Application
game	O
"	O
,	O
adding	O
that	O
ZorkII	O
"	O
has	O
the	O
same	O
outstanding	O
command	O
flexibility	O
,	O
wry	O
humor	O
,	O
and	O
word	O
recognition	O
of	O
Zork	B-Application
"	O
,	O
and	O
concluded	O
that	O
ZorkIII	O
was	O
"	O
perhaps	O
the	O
most	O
entertaining	O
of	O
the	O
three	O
"	O
and	O
"	O
a	O
highwater	O
mark	O
for	O
subtlety	O
and	O
logic	O
"	O
.	O
</s>
<s>
Zork	B-Application
has	O
been	O
described	O
as	O
"	O
by	O
far	O
the	O
most	O
famous	O
piece	O
of	O
[	O
interactive	O
fiction ]	O
"	O
and	O
"	O
the	O
father	O
figure	O
of	O
the	O
genre	O
"	O
.	O
</s>
<s>
Game	O
historian	O
Matt	O
Barton	O
contended	O
that	O
"	O
to	O
say	O
that	O
Zork	B-Application
is	I-Application
an	O
influential	O
adventure	B-Application
game	O
is	O
like	O
saying	O
the	O
Iliad	B-Application
is	O
an	O
influential	O
poem	O
"	O
.	O
</s>
<s>
Nick	O
Montfort	O
,	O
in	O
his	O
book	O
on	O
interactive	O
fiction	O
Twisty	B-Application
Little	I-Application
Passages	I-Application
:	O
An	O
Approach	O
to	O
Interactive	O
Fiction	O
(	O
2003	O
)	O
,	O
suggested	O
that	O
Zorks	B-Application
legacy	O
and	O
influence	O
lay	O
not	O
in	O
its	O
parser	O
or	O
writing	O
,	O
but	O
in	O
the	O
way	O
it	O
modeled	O
the	O
game	O
world	O
as	O
a	O
complex	O
,	O
dynamic	O
space	O
that	O
the	O
player	O
moved	O
through	O
.	O
</s>
<s>
Historians	O
have	O
argued	O
that	O
Zork	B-Application
,	O
along	O
with	O
Colossal	B-Application
Cave	I-Application
Adventure	I-Application
,	O
influenced	O
the	O
creation	O
of	O
the	O
MUD	B-Application
genre	O
,	O
and	O
through	O
it	O
the	O
more	O
recent	O
massively	B-Protocol
multiplayer	I-Protocol
online	I-Protocol
role-playing	I-Protocol
game	I-Protocol
genre	O
.	O
</s>
<s>
Zorks	B-Application
natural	B-Language
language	I-Language
parser	O
has	O
been	O
noted	O
as	O
having	O
a	O
strong	O
personality	O
,	O
and	O
one	O
of	O
the	O
first	O
games	O
to	O
have	O
one	O
.	O
</s>
<s>
It	O
has	O
been	O
cited	O
as	O
starting	O
a	O
strong	O
trend	O
in	O
writing	O
for	O
adventure	B-Application
games	O
having	O
"	O
metafictional	O
humor	O
,	O
and	O
tendency	O
towards	O
self-parody	O
"	O
.	O
</s>
<s>
Decades	O
later	O
Zork	B-Application
is	I-Application
still	O
cited	O
as	O
an	O
inspiration	O
for	O
text	O
interfaces	O
such	O
as	O
chatbots	B-Application
.	O
</s>
<s>
It	O
has	O
also	O
been	O
used	O
,	O
along	O
with	O
other	O
text	O
adventure	B-Application
games	O
,	O
as	O
a	O
framework	O
for	O
testing	O
natural	B-Language
language	I-Language
processing	I-Language
systems	O
.	O
</s>
<s>
Zork	B-Application
was	O
listed	O
on	O
several	O
lists	O
of	O
the	O
best	O
video	O
games	O
more	O
than	O
a	O
decade	O
after	O
release	O
.	O
</s>
<s>
In	O
1992	O
Computer	O
Gaming	O
World	O
added	O
Zork	B-Application
to	O
its	O
Hall	O
of	O
Fame	O
.	O
</s>
<s>
In	O
2016	O
PC	O
Gamer	O
ranked	O
Zork	B-Application
as	O
one	O
of	O
the	O
fifty	O
most	O
important	O
video	O
games	O
ever	O
made	O
for	O
establishing	O
Infocom	O
as	O
a	O
studio	O
and	O
defining	O
an	O
entire	O
generation	O
of	O
adventure	B-Application
games	O
.	O
</s>
<s>
In	O
2007	O
Zork	B-Application
was	O
listed	O
among	O
the	O
ten	O
"	O
game	O
canon	O
"	O
video	O
games	O
selected	O
for	O
preservation	O
by	O
the	O
Library	O
of	O
Congress	O
.	O
</s>
<s>
Zork	B-Application
was	O
the	O
centerpiece	O
of	O
Infocom	O
's	O
game	O
catalog	O
,	O
and	O
Infocom	O
quickly	O
followed	O
it	O
with	O
several	O
more	O
text	O
adventure	B-Application
games	O
using	O
variants	O
of	O
the	O
Zork	B-Application
codebase	O
and	O
the	O
Z-machine	O
,	O
each	O
of	O
which	O
sold	O
tens	O
of	O
thousands	O
of	O
copies	O
.	O
</s>
<s>
By	O
1984	O
,	O
three	O
years	O
after	O
Infocom	O
began	O
self-publishing	O
Zork	B-Application
I	I-Application
,	O
Infocom	O
had	O
fifty	O
full-time	O
employees	O
,	O
US$6million	O
in	O
annual	O
sales	O
,	O
and	O
twelve	O
other	O
games	O
released	O
.	O
</s>
<s>
Infocom	O
internally	O
nicknamed	O
its	O
early	O
games	O
in	O
relation	O
to	O
Zork	B-Application
,	O
such	O
as	O
"	O
Zork	B-Application
:	O
the	O
Mystery	O
"	O
(	O
Deadline	O
,	O
1982	O
)	O
,	O
"	O
Zorks	B-Application
in	O
Space	O
"	O
(	O
Starcross	B-Application
,	O
1982	O
)	O
,	O
and	O
Zork	B-Application
IV	I-Application
(	O
Enchanter	B-Application
,	O
1983	O
)	O
.	O
</s>
<s>
Although	O
Wishbringer	B-Application
:	I-Application
The	I-Application
Magick	I-Application
Stone	I-Application
of	I-Application
Dreams	I-Application
(	O
1985	O
)	O
was	O
ostensibly	O
set	O
in	O
the	O
same	O
world	O
as	O
Zork	B-Application
,	O
the	O
company	O
had	O
not	O
made	O
any	O
more	O
official	O
Zork	B-Application
games	O
,	O
releasing	O
only	O
a	O
Zork	B-Application
Trilogy	I-Application
compilation	O
of	O
all	O
three	O
episodes	O
.	O
</s>
<s>
In	O
1985	O
Infocom	O
diversified	O
into	O
professional	O
software	O
by	O
creating	O
a	O
relational	B-Application
database	I-Application
product	O
called	O
Cornerstone	B-Application
.	O
</s>
<s>
Infocom	O
then	O
created	O
two	O
more	O
Zork	B-Application
games	O
:	O
Beyond	B-Device
Zork	I-Device
:	I-Device
The	I-Device
Coconut	I-Device
of	I-Device
Quendor	I-Device
(	O
1987	O
)	O
,	O
which	O
added	O
a	O
graphical	O
map	O
and	O
more	O
role-playing	O
and	O
combat	O
elements	O
,	O
and	O
Zork	B-Application
Zero	I-Application
:	I-Application
The	I-Application
Revenge	I-Application
of	I-Application
Megaboz	I-Application
(	O
1988	O
)	O
,	O
a	O
prequel	O
game	O
that	O
added	O
graphical	O
elements	O
and	O
menus	O
as	O
well	O
as	O
graphical	O
minigames	O
.	O
</s>
<s>
Activision	O
returned	O
to	O
the	O
series	O
with	O
several	O
graphic	O
adventure	B-Application
games	O
:	O
Return	B-Application
to	I-Application
Zork	I-Application
(	O
1993	O
)	O
,	O
Zork	B-Application
Nemesis	I-Application
:	I-Application
The	I-Application
Forbidden	I-Application
Lands	I-Application
(	O
1996	O
)	O
,	O
and	O
Zork	B-Application
:	I-Application
Grand	I-Application
Inquisitor	I-Application
(	O
1997	O
)	O
.	O
</s>
<s>
It	O
also	O
released	O
Zork	B-Application
:	I-Application
The	I-Application
Undiscovered	I-Application
Underground	I-Application
(	O
1997	O
)	O
,	O
a	O
free	O
text	O
adventure	B-Application
game	O
partially	O
written	O
by	O
original	O
Infocom	O
implementers	O
Michael	O
Berlyn	O
and	O
Marc	O
Blank	O
to	O
promote	O
Zork	B-Application
:	I-Application
Grand	I-Application
Inquisitor	I-Application
.	O
</s>
<s>
In	O
2009	O
Jolt	O
Online	O
Gaming	O
released	O
Legends	B-Protocol
of	I-Protocol
Zork	I-Protocol
,	O
a	O
freemium	O
browser-based	O
online	O
adventure	B-Application
game	O
.	O
</s>
<s>
The	O
original	O
Zork	B-Application
games	O
have	O
been	O
re-released	O
in	O
several	O
compilations	O
since	O
Zork	B-Application
Trilogy	I-Application
.	O
</s>
<s>
They	O
are	O
included	O
in	O
The	B-Device
Lost	I-Device
Treasures	I-Device
of	I-Device
Infocom	I-Device
(	O
1991	O
)	O
,	O
Zork	B-Application
Anthology	O
(	O
1994	O
)	O
,	O
Classic	B-Application
Text	I-Application
Adventure	I-Application
Masterpieces	I-Application
of	I-Application
Infocom	I-Application
(	O
1996	O
)	O
,	O
and	O
Zork	B-Application
Legacy	O
Collection	O
(	O
1996	O
)	O
.	O
</s>
<s>
A	O
graphical	O
port	O
of	O
ZorkI	O
for	O
the	O
PlayStation	B-Device
and	O
Sega	B-Device
Saturn	I-Device
consoles	O
was	O
developed	O
by	O
Arc	O
System	O
Works	O
and	O
published	O
by	O
Shōeisha	O
in	O
Japan	O
in	O
1996	O
,	O
nineteen	O
years	O
after	O
its	O
original	O
release	O
.	O
</s>
<s>
Unofficial	O
versions	O
of	O
Zork	B-Application
have	O
been	O
created	O
for	O
over	O
forty	O
years	O
for	O
a	O
wide	O
range	O
of	O
systems	O
,	O
such	O
as	O
browsers	O
or	O
smart	B-Device
speakers	I-Device
.	O
</s>
<s>
Four	O
gamebooks	O
,	O
written	O
by	O
Infocom	O
developer	O
Steve	O
Meretzky	O
and	O
set	O
in	O
the	O
Zork	B-Application
world	O
,	O
were	O
published	O
in	O
1983	O
–	O
1984	O
:	O
The	O
Forces	O
of	O
Krill	O
(	O
1983	O
)	O
,	O
The	O
Malifestro	O
Quest	O
(	O
1983	O
)	O
,	O
The	O
Cavern	O
of	O
Doom	O
(	O
1983	O
)	O
,	O
and	O
Conquest	O
at	O
Quendor	B-Application
(	O
1984	O
)	O
.	O
</s>
<s>
These	O
books	O
,	O
known	O
collectively	O
as	O
the	O
"	O
Zork	B-Application
books	O
"	O
,	O
are	O
presented	O
as	O
interactive	O
fiction	O
in	O
the	O
style	O
of	O
the	O
Choose	O
Your	O
Own	O
Adventure	B-Application
series	O
,	O
wherein	O
the	O
player	O
makes	O
periodic	O
choices	O
and	O
turns	O
to	O
a	O
page	O
that	O
corresponds	O
to	O
that	O
choice	O
.	O
</s>
<s>
Two	O
novels	O
were	O
published	O
based	O
on	O
the	O
original	O
game	O
:	O
The	O
Zork	B-Application
Chronicles	O
by	O
George	O
Alec	O
Effinger	O
(	O
1990	O
)	O
and	O
The	O
Lost	O
City	O
of	O
Zork	B-Application
by	O
Robin	O
Wayne	O
Bailey	O
(	O
1991	O
)	O
.	O
</s>
<s>
In	O
1996	O
Threshold	O
Entertainment	O
acquired	O
the	O
rights	O
to	O
Zork	B-Application
and	O
announced	O
plans	O
to	O
create	O
a	O
Zork	B-Application
movie	O
and	O
live	O
action	O
TV	O
series	O
,	O
though	O
it	O
was	O
never	O
produced	O
.	O
</s>
