<s>
is	O
a	O
run	O
and	O
gun	O
video	O
game	O
for	O
the	O
Sammy	O
Atomiswave	B-Application
arcade	O
platform	O
in	O
the	O
Metal	B-Application
Slug	I-Application
series	I-Application
.	O
</s>
<s>
One	O
month	O
after	O
the	O
events	O
of	O
Metal	B-Application
Slug	I-Application
3	I-Application
,	O
the	O
threatening	O
presence	O
of	O
General	O
Morden	O
looms	O
over	O
the	O
world	O
once	O
again	O
.	O
</s>
<s>
Marco	O
Rossi	O
and	O
Tarma	O
Roving	O
of	O
the	O
Peregrine	O
Falcon	O
unit	O
reunites	O
with	O
Eri	O
Kasamoto	O
and	O
Fio	O
Germi	O
of	O
SPARROWS	O
as	O
the	O
quartet	O
is	O
ordered	O
to	O
investigate	O
Morden	O
's	O
latest	O
plan	O
,	O
being	O
joined	O
by	O
two	O
new	O
allies	O
named	O
Ralf	O
Jones	O
and	O
Clark	B-Application
Still	I-Application
of	O
the	O
Ikari	B-Application
Warriors	I-Application
.	O
</s>
<s>
Metal	B-Application
Slug	I-Application
6	I-Application
returns	O
to	O
the	O
Rebel-Martian	O
alliance	O
featured	O
in	O
Metal	B-Application
Slug	I-Application
2	O
,	O
X	O
,	O
and	O
3	O
,	O
but	O
on	O
a	O
much	O
broader	O
scale	O
.	O
</s>
<s>
As	O
with	O
previous	O
installments	O
,	O
Metal	B-Application
Slug	I-Application
6	I-Application
adds	O
a	O
number	O
of	O
new	O
Slugs	O
as	O
well	O
as	O
a	O
new	O
weapon	O
,	O
the	O
Zantetsu	O
Sword	O
,	O
which	O
allows	O
the	O
player	O
's	O
melee	O
weapon	O
to	O
emit	O
lethal	O
energy	O
waves	O
that	O
can	O
neutralize	O
enemy	O
firepower	O
.	O
</s>
<s>
Conversely	O
,	O
the	O
sliding	O
technique	O
from	O
Metal	B-Application
Slug	I-Application
5	O
has	O
been	O
removed	O
,	O
and	O
players	O
except	O
Fio	O
and	O
Ralf	O
only	O
receive	O
half	O
as	O
much	O
ammo	O
for	O
special	O
guns	O
.	O
</s>
<s>
Metal	B-Application
Slug	I-Application
6	I-Application
introduces	O
a	O
new	O
play	O
mechanic	O
dubbed	O
the	O
'	O
Weapon	O
Stock	O
System	O
 '	O
.	O
</s>
<s>
A	O
PlayStation	B-Device
2	I-Device
port	O
was	O
released	O
on	O
September	O
14	O
,	O
2006	O
.	O
</s>
<s>
A	O
downloadable	O
version	O
was	O
made	O
available	O
on	O
the	O
PlayStation	O
Store	O
for	O
PlayStation	B-Operating_System
3	I-Operating_System
on	O
May	O
20	O
,	O
2015	O
.	O
</s>
<s>
It	O
is	O
also	O
featured	O
in	O
Metal	B-Application
Slug	I-Application
Anthology	I-Application
for	O
the	B-Operating_System
Wii	I-Operating_System
,	O
PlayStation	B-Device
2	I-Device
and	O
PlayStation	B-Operating_System
Portable	I-Operating_System
.	O
</s>
<s>
In	O
2020	O
,	O
a	O
homebrew	O
conversion	O
was	O
released	O
for	O
the	B-Operating_System
Dreamcast	I-Operating_System
.	O
</s>
