<s>
Stronghold	B-Application
Kingdoms	I-Application
is	O
a	O
Massively	B-Protocol
multiplayer	I-Protocol
online	I-Protocol
real-time	I-Protocol
strategy	I-Protocol
game	I-Protocol
video	O
game	O
with	O
a	O
Medieval	O
castle	O
building	O
theme	O
.	O
</s>
<s>
It	O
was	O
developed	O
by	O
Firefly	O
Studios	O
and	O
based	O
upon	O
their	O
commercially	O
successful	O
and	O
popular	O
Stronghold	B-Application
series	O
of	O
games	O
.	O
</s>
<s>
Firefly	O
Studios	O
started	O
development	O
of	O
Stronghold	B-Application
Kingdoms	I-Application
in	O
2007	O
as	O
their	O
first	O
entry	O
into	O
the	O
MMO	B-Application
genre	O
.	O
</s>
<s>
Stronghold	B-Application
Kingdoms	I-Application
has	O
achieved	O
a	O
Metacritic	O
score	O
of	O
75	O
,	O
indicating	O
generally	O
favorable	O
reviews	O
.	O
</s>
<s>
Gaming	O
XP	O
's	O
review	O
praised	O
how	O
the	O
classic	O
Stronghold	B-Application
format	O
was	O
"	O
implemented	O
very	O
well	O
for	O
this	O
MMO	B-Application
"	O
.	O
</s>
