<s>
Perimeter	B-Application
is	O
a	O
real-time	O
strategy	O
video	O
game	O
developed	O
by	O
Russian	O
studio	O
K-D	O
Lab	O
for	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
In	O
Perimeter	B-Application
,	O
ground	O
must	O
be	O
terraformed	O
before	O
buildings	O
can	O
be	O
built	O
on	O
it	O
.	O
</s>
<s>
Energy	O
Cores	O
can	O
activate	O
the	O
titular	O
Perimeter	B-Application
,	O
an	O
impenetrable	O
barrier	O
that	O
destroys	O
any	O
enemies	O
passing	O
through	O
it	O
.	O
</s>
<s>
The	O
game	O
received	O
"	O
favorable	O
"	O
reviews	O
according	O
to	O
video	O
game	O
review	B-Application
aggregator	I-Application
Metacritic	O
.	O
</s>
<s>
It	O
was	O
nominated	O
for	O
GameSpots	O
annual	O
"	O
Most	O
Innovative	O
Game	O
"	O
award	O
,	O
which	O
went	O
to	O
Katamari	B-Application
Damacy	I-Application
.	O
</s>
<s>
A	O
stand-alone	O
expansion	O
pack	O
titled	O
Perimeter	B-Application
:	O
Emperor	O
's	O
Testament	O
was	O
published	O
by	O
Paradox	O
Interactive	O
and	O
released	O
in	O
2006	O
.	O
</s>
<s>
The	O
expansion	O
pack	O
received	O
"	O
average	O
"	O
reviews	O
according	O
to	O
video	O
game	O
review	B-Application
aggregator	I-Application
Metacritic	O
.	O
</s>
<s>
K-D	O
Lab	O
released	O
a	O
sequel	O
Perimeter	B-Application
2	I-Application
:	I-Application
New	I-Application
Earth	I-Application
in	O
2009	O
.	O
</s>
