<s>
3D	B-Application
Monster	I-Application
Maze	I-Application
is	O
a	O
survival	O
horror	O
computer	O
game	O
developed	O
from	O
an	O
idea	O
by	O
J.K.	O
Greye	O
and	O
programmed	O
by	O
Malcolm	O
Evans	O
and	O
released	O
in	O
1981	B-Application
for	O
the	O
Sinclair	O
ZX81	O
platform	O
with	O
the	O
16KB	O
memory	O
expansion	O
.	O
</s>
<s>
Rendered	O
using	O
low-resolution	B-Algorithm
character	O
block	O
"	O
graphics	O
"	O
,	O
it	O
was	O
one	O
of	O
the	O
first	O
3D	O
games	O
for	O
a	O
home	O
computer	O
,	O
and	O
one	O
of	O
the	O
first	O
games	O
incorporating	O
typical	O
elements	O
of	O
the	O
genre	O
that	O
would	O
later	O
be	O
termed	O
survival	O
horror	O
.	O
</s>
<s>
3D	B-Application
Monster	I-Application
Maze	I-Application
puts	O
the	O
player	O
in	O
a	O
maze	B-Application
with	O
one	O
exit	O
and	O
a	O
hostile	O
monster	O
,	O
the	O
Tyrannosaurus	O
rex	O
.	O
</s>
<s>
There	O
,	O
the	O
player	O
must	O
traverse	O
the	O
maze	B-Application
,	O
from	O
the	O
first-person	O
perspective	O
,	O
and	O
escape	B-Device
through	O
the	O
exit	O
without	O
being	O
eaten	O
.	O
</s>
<s>
J.K.Greye	O
Software	O
went	O
on	O
to	O
become	O
a	O
very	O
successful	O
games	O
company	O
,	O
publishing	O
six	O
Game	O
Tapes	O
for	O
the	O
Sinclair	O
ZX81	O
;	O
two	O
use	O
3D	O
graphics	O
:	O
3D	B-Application
Monster	I-Application
Maze	I-Application
and	O
3D	O
Defender	O
,	O
both	O
designed	O
by	O
J.K.Greye	O
and	O
programmed	O
by	O
Malcolm	O
Evans	O
.	O
</s>
<s>
New	O
Generation	O
Software	O
went	O
on	O
to	O
become	O
a	O
well-known	O
software	O
firm	O
with	O
the	O
Sinclair	O
platform	O
and	O
continued	O
to	O
pioneer	O
the	O
3D	O
gaming	O
technology	O
for	O
ZX81	O
and	O
the	O
later	O
model	O
ZX	B-Operating_System
Spectrum	I-Operating_System
.	O
</s>
<s>
Decades	O
later	O
,	O
it	O
became	O
popular	O
with	O
the	O
retrogaming	O
community	O
,	O
inspiring	O
remakes	O
and	O
fuelling	O
ZX81	O
emulation	B-Application
projects	O
.	O
</s>
<s>
The	O
game	O
uses	O
an	O
18-by-16	O
cell	O
maze	B-Application
which	O
is	O
randomly	O
generated	O
.	O
</s>
<s>
Thereafter	O
,	O
the	O
T	O
.	O
rex	O
may	O
either	O
calm	O
down	O
(	O
if	O
the	O
player	O
goes	O
into	O
a	O
part	O
of	O
the	O
maze	B-Application
that	O
is	O
far	O
enough	O
away	O
)	O
,	O
or	O
become	O
more	O
active	O
as	O
the	O
player	O
comes	O
closer	O
.	O
</s>
<s>
The	O
player	O
's	O
speed	O
is	O
greater	O
than	O
the	O
monster	O
's	O
,	O
thus	O
it	O
is	O
possible	O
to	O
escape	B-Device
by	O
running	O
(	O
unless	O
the	O
player	O
is	O
trapped	O
in	O
a	O
dead	O
end	O
)	O
.	O
</s>
<s>
The	O
player	O
can	O
manually	O
map	O
the	O
maze	B-Application
on	O
a	O
piece	O
of	O
paper	O
with	O
each	O
step	O
,	O
but	O
this	O
becomes	O
increasingly	O
difficult	O
as	O
the	O
pace	O
increases	O
.	O
</s>
<s>
Points	O
are	O
also	O
given	O
upon	O
successfully	O
getting	O
away	O
through	O
an	O
exit	O
and	O
into	O
another	O
maze	B-Application
.	O
</s>
<s>
When	O
the	O
game	O
ends	O
,	O
the	O
player	O
is	O
informed	O
about	O
being	O
"	O
sentenced	O
to	O
roam	O
the	O
maze	B-Application
forever	O
"	O
,	O
and	O
then	O
can	O
either	O
"	O
appeal	O
"	O
or	O
continue	O
playing	O
again	O
in	O
the	O
last	O
maze	B-Application
.	O
</s>
<s>
If	O
the	O
appeal	O
is	O
attempted	O
,	O
it	O
is	O
rejected	O
with	O
50%	O
probability	O
,	O
in	O
which	O
case	O
the	O
player	O
is	O
sent	O
back	O
to	O
roam	O
the	O
previous	O
maze	B-Application
again	O
.	O
</s>
<s>
An	O
appeal	O
which	O
is	O
accepted	O
effectively	O
results	O
in	O
the	O
computer	O
self-reset	B-Device
via	O
BASIC	B-Language
's	O
NEW	O
statement	O
.	O
</s>
<s>
The	O
graphical	O
view	O
,	O
animated	O
in	O
real	O
time	O
at	O
around	O
6frames	O
per	O
second	O
,	O
is	O
composed	O
of	O
8×8	O
pixel	B-Algorithm
black-and-white	O
characters	O
,	O
so	O
the	O
view	O
is	O
roughly	O
square	O
,	O
taking	O
a	O
25×24	O
area	O
on	O
the	O
32×24	O
text	O
screen	O
.	O
</s>
<s>
Sub-character	O
resolution	O
of	O
the	O
ZX81	O
pseudo-graphics	B-Data_Structure
character	B-General_Concept
set	I-General_Concept
makes	O
the	O
resolution	O
doubled	O
in	O
each	O
dimension	O
(	O
making	O
the	O
view	O
consist	O
of	O
50×48	O
"	O
larger	O
pixels	B-Algorithm
"	O
)	O
.	O
</s>
<s>
The	O
game	O
's	O
3D	O
engine	O
and	O
the	O
random	O
maze	B-Application
creation	O
code	O
is	O
written	O
in	O
Z80	B-General_Concept
machine	B-Language
code	I-Language
,	O
produced	O
with	O
an	O
assembler	O
.	O
</s>
<s>
This	O
is	O
augmented	O
by	O
several	O
dozen	O
BASIC	B-Language
lines	O
for	O
less	O
critical	O
tasks	O
,	O
such	O
as	O
the	O
initial	O
greetings	O
and	O
the	O
game	O
legend	O
animation	O
inter-line	O
delay	O
.	O
</s>
<s>
The	O
machine	B-Language
code	I-Language
subroutines	O
block	O
is	O
embedded	O
into	O
the	O
BASIC	B-Language
line0	O
,	O
beginning	O
with	O
a	O
REM	O
(	O
BASIC	B-Language
comment	O
)	O
statement	O
,	O
making	O
the	O
interpreter	B-Application
step	O
over	O
it	O
.	O
</s>
<s>
If	O
,	O
by	O
accident	O
,	O
one	O
tries	O
to	O
edit	O
the	O
line	O
via	O
the	O
BASIC	B-Language
line	B-Application
editor	I-Application
,	O
the	O
changes	O
will	O
not	O
be	O
accepted	O
since	O
0	O
is	O
an	O
invalid	O
line	O
number	O
.	O
</s>
<s>
Such	O
code	O
is	O
typically	O
created	O
by	O
first	O
creating	O
a	O
line	O
with	O
a	O
valid	O
number	O
,	O
and	O
then	O
modifying	O
the	O
number	O
field	O
in	O
the	O
BASIC	B-Language
program	O
area	O
using	O
direct	O
memory	O
manipulation	O
,	O
such	O
as	O
POKE	B-Language
.	O
</s>
<s>
No	O
copy	B-Application
protection	I-Application
is	O
embedded	O
into	O
the	O
game	O
;	O
moreover	O
,	O
the	O
magnetic	O
tapes	O
of	O
the	O
time	O
being	O
unreliable	O
,	O
one	O
could	O
reuse	O
the	O
save	O
entry	O
point	O
in	O
the	O
BASIC	B-Language
code	O
(	O
that	O
was	O
used	O
by	O
the	O
original	O
developers	O
to	O
have	O
the	O
game	O
auto-run	O
upon	O
being	O
loaded	O
by	O
the	O
user	O
)	O
in	O
order	O
to	O
save	O
another	O
program	O
copy	O
to	O
the	O
tape	O
(	O
for	O
archival	O
and	O
backup	B-Protocol
purposes	O
)	O
.	O
</s>
<s>
The	O
game	O
is	O
controlled	O
by	O
three	O
of	O
the	O
keyboard	O
cursor	B-Application
control	O
keys	O
(	O
left	O
,	O
forward	O
and	O
right	O
,	O
respectively	O
5	O
,	O
7	O
and	O
8	O
on	O
the	O
ZX81	O
keyboard	O
)	O
.	O
</s>
<s>
The	O
game	O
speed	O
can	O
also	O
be	O
controlled	O
according	O
to	O
the	O
original	O
cassette	O
inlay	O
,	O
the	O
BASIC	B-Language
line370	O
has	O
a	O
hardwired	O
constant	O
determining	O
a	O
busy	B-Operating_System
waiting	I-Operating_System
loop	O
delay	O
.	O
</s>
<s>
3D	B-Application
Monster	I-Application
Maze	I-Application
was	O
the	O
first	O
game	O
programmed	O
by	O
Malcolm	O
Evans	O
based	O
on	O
a	O
design	O
by	O
J.K.Greye	O
.	O
</s>
<s>
Malcolm	O
developed	O
basic	B-Language
aspects	O
of	O
the	O
game	O
to	O
test	O
what	O
the	O
computer	O
was	O
capable	O
of	O
,	O
and	O
completed	O
it	O
after	O
adding	O
design	O
features	O
suggested	O
by	O
J.K.Greye	O
,	O
including	O
adding	O
the	O
T.Rex	O
and	O
turning	O
the	O
Maze	B-Application
into	O
a	O
game	O
.	O
</s>
<s>
Friends	O
persuaded	O
Malcolm	O
that	O
the	O
game	O
was	O
of	O
high	O
enough	O
quality	O
to	O
sell	O
and	O
it	O
was	O
eventually	O
released	O
by	O
J.K.Greye	O
Software	O
in	O
late	O
1981	B-Application
.	O
</s>
<s>
After	O
releasing	O
3D	O
Defender	O
and	O
Breakout	O
for	O
the	O
ZX81	O
,	O
Malcolm	O
switched	O
the	O
development	O
efforts	O
from	O
ZX81	O
to	O
ZX	B-Operating_System
Spectrum	I-Operating_System
as	O
the	O
latter	O
model	O
was	O
released	O
onto	O
the	O
market	O
.	O
</s>
<s>
In	O
addition	O
to	O
republishing	O
3D	B-Application
Monster	I-Application
Maze	I-Application
,	O
the	O
new	O
firm	O
also	O
released	O
such	O
game	O
titles	O
as	O
Escape	B-Device
,	O
3D	B-Application
Tunnel	I-Application
,	O
Knot	B-Application
in	I-Application
3D	I-Application
,	O
Corridors	B-Application
of	I-Application
Genon	I-Application
,	O
Trashman	B-Application
and	O
Travel	O
with	O
Trashman	B-Application
,	O
Light	O
Magic	O
,	O
Jonah	O
Barrington	O
's	O
Squash	O
,	O
The	O
Custard	O
Kid	O
and	O
Cliff	O
Hanger	O
.	O
</s>
<s>
Even	O
though	O
it	O
did	O
not	O
use	O
the	O
undocumented	O
hi-res	B-Algorithm
graphics	O
feature	O
of	O
the	O
ZX81	O
,	O
and	O
rendered	O
the	O
scene	O
with	O
pseudo-graphics	B-Data_Structure
characters	O
(	O
available	O
in	O
the	O
standard	O
ZX81	O
character	B-General_Concept
set	I-General_Concept
)	O
,	O
the	O
game	O
was	O
considered	O
to	O
be	O
a	O
remarkable	O
achievement	O
,	O
utilising	O
the	O
machine	O
's	O
capabilities	O
to	O
its	O
best	O
:	O
</s>
<s>
Soon	O
the	O
Sinclair	O
platform	O
users	O
began	O
switching	O
over	O
to	O
the	O
newer	O
ZX	B-Operating_System
Spectrum	I-Operating_System
,	O
which	O
had	O
better	O
graphics	O
resolution	O
and	O
colour	O
,	O
bigger	O
RAM	B-Architecture
and	O
ROM	B-Device
,	O
as	O
well	O
as	O
sound	O
capability	O
and	O
a	O
sleeker	O
look	O
and	O
feel	O
.	O
</s>
<s>
Some	O
people	O
still	O
continued	O
to	O
use	O
their	O
ZX81	O
,	O
and	O
even	O
the	O
Spectrum	O
users	O
gave	O
credit	O
to	O
3D	B-Application
Monster	I-Application
Maze	I-Application
as	O
the	O
game	O
that	O
brought	O
the	O
3D	O
aspect	O
into	O
the	O
home	O
computer	O
gaming	O
:	O
</s>
<s>
Monster	O
Maze	B-Application
's	O
praises	O
brought	O
recognition	O
to	O
Malcolm	O
Evans	O
and	O
his	O
firm	O
,	O
New	O
Generation	O
Software	O
,	O
which	O
continued	O
releasing	O
further	O
games	O
that	O
further	O
improved	O
the	O
3D	O
gaming	O
experience	O
.	O
</s>
<s>
Even	O
when	O
later	O
hit	O
games	O
by	O
N.G.S.	O
,	O
such	O
as	O
Trashman	B-Application
,	O
were	O
covered	O
by	O
the	O
gaming	O
media	O
reviews	O
,	O
3D	B-Application
Monster	I-Application
Maze	I-Application
was	O
remembered	O
as	O
the	O
landmark	O
impressive	O
start	O
:	O
</s>
<s>
Edge	O
in	O
2006	O
stated	O
that	O
3D	B-Application
Monster	I-Application
Maze	I-Application
"	O
is	O
the	O
original	O
survival	O
horror	O
game	O
"	O
,	O
writing	O
"	O
Ask	O
any	O
player	O
and	O
they	O
'll	O
tell	O
you	O
what	O
3D	B-Application
Monster	I-Application
Maze	I-Application
was	O
chiefly	O
about	O
:	O
fear	O
,	O
panic	O
,	O
terror	O
and	O
facing	O
an	O
implacable	O
,	O
relentless	O
foe	O
who	O
's	O
going	O
to	O
get	O
you	O
in	O
the	O
end.	O
"	O
</s>
<s>
With	O
ZX81	O
games	O
played	O
mostly	O
in	O
emulated	B-Application
environments	O
by	O
the	O
retrogaming	O
community	O
,	O
it	O
still	O
receives	O
enthusiastic	O
reviews	O
,	O
even	O
while	O
modern	O
high-end	O
gaming	O
consoles	O
and	O
home	O
computers	O
provide	O
much	O
richer	O
capabilities	O
for	O
one	O
's	O
immersion	B-Application
into	O
a	O
first-person	O
3D	O
game	O
:	O
</s>
