<s>
Zombie	O
Defense	O
Squadron	O
)	O
is	O
a	O
vertical	O
scrolling	O
shooter	O
video	O
game	O
developed	O
by	O
SnopsGames	O
for	O
the	B-Operating_System
Xbox	I-Operating_System
360	I-Operating_System
’s	O
Xbox	B-Device
Live	I-Device
Indie	I-Device
Games	I-Device
service	O
and	O
released	O
on	O
September	O
11	O
,	O
2012	O
.	O
</s>
<s>
was	O
originally	O
conceived	O
when	O
web	O
designer	O
Mike	O
Walz	O
was	O
experimenting	O
in	O
SilverLight	B-Application
with	O
the	O
idea	O
for	O
web	O
development	O
on	O
a	O
SHMUP	O
.	O
</s>
<s>
Walz	O
cites	O
old-school	O
shoot	O
'	O
em	O
ups	O
such	O
as	O
Twin	B-Application
Cobra	I-Application
,	O
Thunder	B-Application
Force	I-Application
,	O
Soldier	B-Device
Blade	I-Device
and	O
Blazing	B-Device
Lazers	I-Device
as	O
large	O
influences	O
on	O
him	O
growing	O
up	O
.	O
</s>
<s>
The	O
game	O
ranked	O
at	O
number	O
five	O
on	O
com	O
's	O
Top	O
10	O
Xbox	B-Device
Live	I-Device
Indie	I-Device
Games	I-Device
of	O
2012	O
,	O
noting	O
that	O
it	O
stands	O
among	O
as	O
one	O
of	O
the	O
best	O
(	O
shmups	O
)	O
in	O
its	O
crowd	O
.	O
</s>
