<s>
Epic	B-Operating_System
Citadel	I-Operating_System
is	O
a	O
tech	O
demo	O
developed	O
by	O
Epic	O
Games	O
to	O
demonstrate	O
the	O
Unreal	O
Engine	O
3	O
running	O
on	O
Apple	B-Operating_System
iOS	I-Operating_System
,	O
within	O
Adobe	B-Operating_System
Flash	I-Operating_System
Player	I-Operating_System
Stage3D	B-Operating_System
and	O
using	O
HTML5	B-Application
WebGL	B-Library
technologies	O
.	O
</s>
<s>
It	O
was	O
also	O
released	O
for	O
Android	B-Application
on	O
January	O
29	O
,	O
2013	O
.	O
</s>
<s>
Epic	B-Operating_System
Citadel	I-Operating_System
was	O
a	O
precursor	O
to	O
the	O
video	O
game	O
Infinity	B-Application
Blade	I-Application
for	O
iOS	B-Operating_System
,	O
which	O
was	O
released	O
on	O
December	O
9	O
,	O
2010	O
.	O
</s>
<s>
On	O
March	O
7	O
,	O
2012	O
,	O
Epic	O
released	O
Epic	B-Operating_System
Citadel	I-Operating_System
for	O
Flash	B-Operating_System
,	O
to	O
demonstrate	O
Unreal	O
Engine	O
3	O
running	O
within	O
Adobe	B-Operating_System
Flash	I-Operating_System
Player	I-Operating_System
in	O
a	O
web	B-Application
browser	I-Application
environment	O
.	O
</s>
<s>
It	O
was	O
the	O
first	O
gaming	O
3D	O
engine	O
to	O
be	O
ported	O
to	O
run	O
within	O
Flash	B-Operating_System
Player	I-Operating_System
,	O
using	O
the	O
CrossBridge	B-Language
cross-compiler	O
(	O
also	O
known	O
as	O
Alchemy	B-Language
)	O
.	O
</s>
<s>
On	O
January	O
29	O
,	O
2013	O
,	O
the	O
app	O
was	O
launched	O
for	O
Google	B-Application
Android	I-Application
(	O
version	O
2.3	O
+	O
)	O
,	O
with	O
exclusive	O
benchmarking	O
features	O
,	O
and	O
was	O
downloadedable	O
from	O
the	O
Google	B-Application
Play	I-Application
store	I-Application
.	O
</s>
<s>
The	O
iOS	B-Operating_System
version	O
was	O
updated	O
to	O
version	O
1.1	O
,	O
adding	O
support	O
for	O
the	O
iPhone	O
5/iPod	O
Touch	O
(	O
fifth	O
generation	O
)	O
as	O
well	O
as	O
optimized	O
graphics	O
for	O
the	O
iPad	O
with	O
Retina	O
Display	O
.	O
</s>
<s>
Using	O
additional	O
technologies	O
such	O
as	O
the	O
C/C	O
++	O
to	O
JavaScript	O
cross-compiler	O
Emscripten	B-Language
,	O
the	O
application	O
was	O
ported	O
to	O
HTML5	B-Application
supporting	O
run	O
time	O
environments	O
such	O
as	O
the	O
Firefox	O
web	B-Application
browser	I-Application
.	O
</s>
