<s>
It	O
was	O
released	O
for	O
the	O
MSX	B-Operating_System
computer	O
,	O
the	O
Family	B-Device
Computer	I-Device
Disk	I-Device
System	I-Device
,	O
the	O
Nintendo	O
Entertainment	O
System	O
,	O
and	O
for	O
the	O
Virtual	B-Application
Console	I-Application
.	O
</s>
<s>
It	O
was	O
reworked	O
for	O
the	O
MSX2	B-Operating_System
computer	O
as	O
Zanac	B-Device
EX	I-Device
and	O
for	O
the	O
PlayStation	B-Device
as	O
Zanac	B-Device
X	I-Device
Zanac	I-Device
.	O
</s>
<s>
Players	O
fly	O
a	O
lone	O
starfighter	O
,	O
dubbed	O
the	O
AFX-6502	O
Zanac	B-Device
,	O
through	O
twelve	O
levels	O
;	O
their	O
goal	O
is	O
to	O
destroy	O
the	O
System	O
—	O
a	O
part-organic	O
,	O
part-mechanical	O
entity	O
bent	O
on	O
destroying	O
mankind	O
.	O
</s>
<s>
Zanac	B-Device
was	O
developed	O
by	O
main	O
core	O
developers	O
of	O
Compile	O
,	O
including	O
Masamitsu	O
"	O
Moo	O
"	O
Niitani	O
,	O
Koji	O
"	O
Janus	O
"	O
Teramoto	O
,	O
and	O
Takayuki	O
"	O
Jemini	O
"	O
Hirono	O
.	O
</s>
<s>
All	O
of	O
these	O
developers	O
went	O
on	O
to	O
make	O
other	O
popular	O
similarly	O
based	O
games	O
such	O
as	O
The	B-Application
Guardian	I-Application
Legend	I-Application
,	O
Blazing	B-Device
Lazers	I-Device
,	O
and	O
the	O
Puyo	B-Application
Puyo	I-Application
series	O
.	O
</s>
<s>
It	O
has	O
been	O
praised	O
for	O
its	O
unique	O
adaptive	O
artificial	B-Application
intelligence	I-Application
,	O
in	O
which	O
the	O
game	O
automatically	O
adjusts	O
the	O
difficulty	O
level	O
according	O
to	O
the	O
player	O
's	O
skill	O
level	O
,	O
rate	O
of	O
fire	O
and	O
the	O
ship	O
's	O
current	O
defensive	O
status/capability	O
.	O
</s>
<s>
In	O
Zanac	B-Device
,	O
the	O
player	O
controls	O
the	O
spaceship	O
AFX-6502	O
Zanac	B-Device
as	O
it	O
flies	O
through	O
various	O
planets	O
,	O
space	O
stations	O
,	O
and	O
outer	O
space	O
and	O
through	O
an	O
armada	O
of	O
enemies	O
comprising	O
the	O
defenses	O
of	O
the	O
game	O
's	O
main	O
antagonist	O
—	O
the	O
"	O
System	O
"	O
.	O
</s>
<s>
Zanac	B-Device
has	O
a	O
continue	O
option	O
which	O
allows	O
players	O
to	O
restart	O
the	O
game	O
from	O
the	O
level	O
in	O
which	O
they	O
lost	O
all	O
their	O
lives	O
.	O
</s>
<s>
Enemies	O
in	O
Zanac	B-Device
include	O
meteors	O
,	O
various	O
bullet-shooting	O
enemy	O
aircraft	O
,	O
bullet-resistant	O
disks	O
,	O
ground	O
turrets	O
,	O
and	O
reconnaissance	O
planes	O
.	O
</s>
<s>
The	O
distinguishing	O
aspect	O
of	O
Zanac'''s	O
gameplay	O
is	O
its	O
unique	O
enemy	O
artificial	B-Application
intelligence	I-Application
,	O
called	O
the	O
"	O
Automatic	O
Level	O
of	O
Difficulty	O
Control	O
"	O
or	O
ALC	O
.	O
</s>
<s>
The	O
plot	O
of	O
Zanac	B-Device
revolves	O
around	O
the	O
"	O
System	O
"	O
—	O
a	O
device	O
figuratively	O
similar	O
to	O
Pandora	B-Application
's	I-Application
box	I-Application
.	O
</s>
<s>
The	O
AFX-6502	O
Zanac	B-Device
,	O
the	O
most	O
advanced	O
starfighter	O
ever	O
produced	O
,	O
is	O
launched	O
on	O
a	O
desperate	O
mission	O
to	O
fight	O
its	O
way	O
to	O
the	O
heart	O
of	O
the	O
System	O
and	O
shut	O
it	O
down	O
.	O
</s>
<s>
Release	O
historyZanac	O
was	O
initially	O
released	O
in	O
1986	O
for	O
the	O
MSX	B-Operating_System
computer	O
by	O
the	O
Japanese	O
video	O
game	O
company	O
Compile	O
—	O
the	O
same	O
company	O
responsible	O
for	O
other	O
games	O
such	O
as	O
Blazing	B-Device
Lazers	I-Device
,	O
Devil	B-Application
's	I-Application
Crush	I-Application
,	O
and	O
the	O
Puyo	B-Application
Puyo	I-Application
series	O
.	O
</s>
<s>
Compile	O
then	O
re-released	O
the	O
game	O
for	O
the	O
MSX2	B-Operating_System
computer	O
later	O
that	O
same	O
year	O
as	O
Zanac	B-Device
Ex	I-Device
,	O
which	O
featured	O
improved	O
graphics	O
(	O
with	O
smooth	O
scrolling	O
)	O
and	O
extended	O
music	O
over	O
the	O
original	O
MSX	B-Operating_System
version	O
.	O
</s>
<s>
Zanac	B-Device
was	O
then	O
ported	O
and	O
heavily	O
reworked	O
again	O
for	O
release	O
on	O
the	O
Family	B-Device
Computer	I-Device
Disk	I-Device
System	I-Device
in	O
Japan	O
on	O
November	O
11	O
,	O
1986	O
,	O
and	O
then	O
in	O
North	O
America	O
for	O
the	O
NES	B-Language
in	O
October	O
1987	O
.	O
</s>
<s>
The	O
NES	B-Language
version	O
was	O
later	O
re-released	O
for	O
Wii	B-Operating_System
's	O
Virtual	B-Application
Console	I-Application
service	O
on	O
December	O
3	O
,	O
2007	O
,	O
and	O
published	O
by	O
D4	O
Enterprise	O
.	O
</s>
<s>
This	O
version	O
is	O
identical	O
to	O
the	O
NES	B-Language
version	O
released	O
in	O
1987	O
.	O
</s>
<s>
Compile	O
released	O
a	O
compilation	O
titled	O
Zanac	B-Device
X	I-Device
Zanac	I-Device
for	O
Sony	O
's	O
PlayStation	B-Device
console	I-Device
in	O
Japan	O
on	O
November	O
29	O
,	O
2001	O
,	O
to	O
commemorate	O
the	O
15th	O
anniversary	O
of	O
the	O
original	O
.	O
</s>
<s>
This	O
compilation	O
features	O
an	O
updated	O
version	O
of	O
Zanac	B-Device
—	O
titled	O
Zanac	B-Device
Neo	I-Device
—	O
and	O
three	O
versions	O
of	O
the	O
NES	B-Language
version	O
of	O
the	O
game	O
,	O
including	O
a	O
version	O
featuring	O
enhanced	O
graphics	O
and	O
sound	O
.	O
</s>
<s>
A	O
version	O
of	O
the	O
game	O
was	O
released	O
on	O
the	O
Nintendo	B-Application
Switch	I-Application
via	O
the	O
G-Mode	O
Archives	O
series	O
in	O
January	O
2021	O
.	O
</s>
<s>
Reception	O
and	O
legacyZanac	O
,	O
in	O
retrospect	O
,	O
has	O
been	O
considered	O
a	O
unique	O
shoot	O
'	O
em	O
up	O
game	O
,	O
combining	O
gameplay	O
elements	O
from	O
games	O
such	O
as	O
Xevious	B-Application
,	O
especially	O
with	O
the	O
extensive	O
power-up	O
system	O
and	O
vertical-scrolling	O
gameplay	O
that	O
features	O
both	O
air	O
and	O
ground	O
targets	O
.	O
</s>
<s>
Brett	O
Alan	O
Weiss	O
of	O
Allgame	O
praised	O
Zanac	B-Device
,	O
calling	O
it	O
an	O
extremely	O
fast-paced	O
shooter	O
in	O
which	O
the	O
player	O
is	O
almost	O
completely	O
surrounded	O
by	O
enemy	O
ships	O
and	O
bullets	O
.	O
</s>
<s>
He	O
praises	O
the	O
game	O
for	O
its	O
music	O
which	O
seems	O
to	O
flow	O
along	O
with	O
the	O
action	O
of	O
the	O
game	O
;	O
he	O
calls	O
the	O
music	O
"	O
at	O
least	O
as	O
close	O
as	O
you	O
can	O
get	O
to	O
a	O
Zen	O
moment	O
while	O
playing	O
a	O
shooting	O
game	O
on	O
the	O
NES	B-Language
"	O
.	O
</s>
<s>
Frank	O
Provo	O
of	O
GameSpot	O
lauded	O
Zanac	B-Device
for	O
its	O
difficulty	O
level	O
,	O
its	O
ability	O
to	O
handle	O
many	O
sprites	O
on	O
the	O
screen	O
without	O
slowdown	O
or	O
other	O
glitches	O
,	O
and	O
its	O
unique	O
AI	B-Application
,	O
which	O
placed	O
this	O
game	O
in	O
a	O
subgenre	O
of	O
its	O
own	O
.	O
</s>
<s>
In	O
addition	O
,	O
Weiss	O
says	O
that	O
enemies	O
in	O
Zanac''	O
,	O
while	O
fearsome	O
,	O
"	O
do	O
n't	O
have	O
much	O
personality	O
"	O
.	O
</s>
