<s>
Depthcharge	B-Application
is	O
a	O
single-player	O
arcade	O
game	O
released	O
in	O
1977	O
by	O
Gremlin	O
Industries	O
.	O
</s>
<s>
The	O
game	O
,	O
which	O
uses	O
a	O
black-and-white	O
CRT	O
display	O
,	O
presents	O
the	O
player	O
with	O
a	O
cut-away	O
view	O
of	O
a	O
section	O
of	O
ocean	O
,	O
on	O
the	O
surface	O
of	O
which	O
is	O
a	O
destroyer	B-Application
with	O
submarines	O
passing	O
beneath	O
it	O
.	O
</s>
<s>
The	O
player	O
drops	O
depth	B-Device
charges	I-Device
(	O
up	O
to	O
six	O
at	O
a	O
time	O
)	O
to	O
destroy	O
the	O
submarines	O
and	O
moves	O
the	O
ship	O
back	O
and	O
forth	O
in	O
order	O
to	O
avoid	O
the	O
submarines	O
 '	O
mines	O
.	O
</s>
