<s>
Hammerfight	B-Application
,	O
previously	O
known	O
as	O
Hammerfall	B-Application
,	O
is	O
a	O
2-dimensional	O
physics-based	O
video	O
game	O
published	O
by	O
Kranx	O
Productions	O
and	O
1C	O
for	O
Windows	B-Application
in	O
2009	O
.	O
</s>
<s>
It	O
was	O
re-released	O
as	O
a	O
cross-platform	B-Operating_System
game	O
in	O
the	O
third	O
Humble	O
Indie	O
Bundle	O
in	O
2011	O
,	O
at	O
which	O
time	O
the	O
underlying	O
engine	O
,	O
Haaf	O
's	O
Game	O
Engine	O
was	O
made	O
cross-platform	B-Operating_System
and	O
open-sourced	O
.	O
</s>
<s>
In	O
the	O
physics-based	O
gameplay	O
,	O
the	O
player	O
swings	O
large	O
melee	B-Application
weapons	O
and	O
relies	O
on	O
centripetal	O
force	O
to	O
give	O
the	O
object	O
enough	O
kinetic	O
energy	O
to	O
destroy	O
enemies	O
.	O
</s>
<s>
The	O
demo	O
release	O
had	O
six	O
main	O
types	O
of	O
weapons	O
-	O
four	O
melee	B-Application
and	O
two	O
ranged	O
.	O
</s>
<s>
The	O
game	O
was	O
initially	O
released	O
by	O
Kranx	O
Productions	O
and	O
1C	O
for	O
Windows	B-Application
only	O
.	O
</s>
<s>
For	O
the	O
bundle	O
,	O
Ryan	O
C	O
.	O
Gordon	O
ported	O
the	O
game	O
and	O
the	O
underlying	O
game	O
engine	O
,	O
Haaf	O
's	O
Game	O
Engine	O
(	O
HGE	O
)	O
,	O
to	O
Linux	B-Application
and	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
.	O
</s>
<s>
Following	O
that	O
,	O
Relish	O
Games	O
and	O
Ryan	O
Gordon	O
released	O
the	O
source	O
code	O
of	O
their	O
versions	O
of	O
the	O
engine	O
under	O
the	O
zlib	B-License
free	B-License
software	I-License
license	I-License
in	O
August/September	O
2011	O
.	O
</s>
