<s>
Alien	B-Application
Shooter	I-Application
is	O
an	O
isometric	B-Application
,	O
top-down	O
shooter	O
video	O
game	O
developed	O
and	O
released	O
by	O
Sigma	O
Team	O
,	O
a	O
Russian	O
games	O
development	O
studio	O
.	O
</s>
<s>
Released	O
on	O
May	O
18	O
,	O
2003	O
,	O
it	O
was	O
initially	O
available	O
on	O
Microsoft	B-Application
Windows	I-Application
,	O
iOS	B-Application
,	O
and	O
Android	B-Application
.	O
</s>
<s>
The	O
sequel	O
,	O
Alien	B-Application
Shooter	I-Application
:	I-Application
Vengeance	I-Application
,	O
was	O
released	O
in	O
2007	O
.	O
</s>
<s>
In	O
June	O
2015	O
,	O
Sigma	O
Team	O
and	O
co-developer	O
8floor	O
released	O
a	O
PlayStation	B-Device
Vita	I-Device
port	O
of	O
the	O
game	O
.	O
</s>
<s>
On	O
January	O
22	O
,	O
2020	O
,	O
Sigma	O
Team	O
released	O
Alien	B-Application
Shooter	I-Application
2	I-Application
:	O
The	O
Legend	O
,	O
a	O
reboot	O
of	O
the	O
previous	O
sequels	O
with	O
updated	O
graphics	O
,	O
gameplay	O
,	O
and	O
new	O
content	O
.	O
</s>
<s>
Alien	B-Application
Shooter	I-Application
is	O
presented	O
in	O
a	O
top-down	O
,	O
third-person	O
view	O
(	O
3/4	O
perspective	O
)	O
,	O
and	O
takes	O
place	O
across	O
nine	O
levels	O
of	O
increasing	O
difficulty	O
.	O
</s>
<s>
Later	O
levels	O
feature	O
teleportation	B-General_Concept
devices	O
,	O
which	O
spawn	O
enemies	O
indefinitely	O
,	O
and	O
can	O
only	O
be	O
destroyed	O
by	O
special	O
explosives	O
scattered	O
throughout	O
the	O
level	O
.	O
</s>
<s>
As	O
the	O
protagonist	O
explores	O
the	O
lab	O
,	O
the	O
root	O
of	O
the	O
problem	O
is	O
revealed	O
to	O
be	O
a	O
malfunction	O
with	O
an	O
experimental	O
teleportation	B-General_Concept
device	O
.	O
</s>
<s>
Fight	O
for	O
Life	O
:	O
Six	O
months	O
after	O
the	O
events	O
of	O
Alien	B-Application
Shooter	I-Application
,	O
it	O
becomes	O
clear	O
that	O
the	O
alien	O
creatures	O
have	O
returned	O
.	O
</s>
<s>
In	O
2012	O
,	O
GameSpot	O
gave	O
Alien	B-Application
Shooter	I-Application
a	O
6.4	O
out	O
of	O
10	O
rating	O
,	O
writing	O
,	O
"	O
While	O
the	O
game	O
makes	O
good	O
on	O
its	O
promise	O
of	O
giving	O
you	O
aliens	O
to	O
shoot	O
,	O
the	O
end	O
result	O
is	O
very	O
repetitive.	O
"	O
</s>
<s>
Alien	B-Application
Shooter	I-Application
-	O
The	O
BeginningA	O
mobile	O
version	O
of	O
the	O
original	O
PC	O
game	O
that	O
has	O
been	O
ported	O
to	O
iOS	B-Application
.	O
</s>
<s>
Alien	B-Application
Shooter	I-Application
RevisitedA	O
remaster	O
of	O
the	O
original	O
Alien	B-Application
Shooter	I-Application
released	O
on	O
April	O
15	O
,	O
2009	O
.	O
</s>
<s>
Alien	B-Application
Shooter	I-Application
2	I-Application
:	O
ReloadedReleased	O
in	O
March	O
14	O
,	O
2009	O
,	O
it	O
offers	O
two	O
new	O
missions	O
as	O
well	O
as	O
an	O
individual	O
shooting	O
mode	O
called	O
Gun	O
Stand	O
.	O
</s>
<s>
Alien	B-Application
Shooter	I-Application
2	I-Application
:	O
Conscription	O
—	O
Released	O
July	O
3	O
,	O
2010	O
,	O
it	O
's	O
an	O
add-on	O
to	O
the	O
Alien	B-Application
Shooter	I-Application
2	I-Application
Series	O
.	O
</s>
<s>
Zombie	B-Application
ShooterAlien	O
Shooter	O
is	O
similar	O
to	O
this	O
top-down	O
shooter	O
that	O
was	O
released	O
on	O
December	O
29	O
,	O
2007	O
.	O
</s>
<s>
It	O
follows	O
a	O
similar	O
premise	O
as	O
Alien	B-Application
Shooter	I-Application
;	O
The	O
human	O
race	O
is	O
in	O
grave	O
danger	O
.	O
</s>
<s>
After	O
becoming	O
infected	O
with	O
their	O
own	O
mutated	O
contagion	O
,	O
they	O
became	O
zombies	B-Application
.	O
</s>
<s>
Alien	B-Application
Shooter	I-Application
2	I-Application
:	O
The	O
Legend	O
-	O
remastered	O
version	O
of	O
Alien	B-Application
Shooter	I-Application
2	I-Application
:	O
Conscription	O
and	O
Vengeance/Reloaded	O
,	O
released	O
in	O
January	O
2020	O
.	O
</s>
<s>
Alien	B-Application
Shooter	I-Application
:	O
TD	O
-	O
tower	O
defense	O
game	O
based	O
on	O
the	O
series	O
,	O
released	O
for	O
multiple	O
platforms	O
in	O
2017	O
.	O
</s>
<s>
Alien	B-Application
Shooter	I-Application
2	I-Application
:	O
New	O
Era	O
-	O
a	O
direct	O
sequels	O
of	O
Alien	B-Application
Shooter	I-Application
2	I-Application
The	O
Legend	O
,	O
before	O
the	O
events	O
of	O
Alien	B-Application
Shooter	I-Application
3	O
.	O
</s>
