<s>
Phantom	B-Application
Slayer	I-Application
is	O
a	O
video	O
game	O
released	O
by	O
Med	O
Systems	O
in	O
1982	B-Application
for	O
the	O
TRS-80	B-Device
Color	I-Device
Computer	I-Device
and	O
Dragon	B-Device
32/64	I-Device
.	O
</s>
<s>
Written	O
by	O
Ken	O
Kalish	O
,	O
Phantom	B-Application
Slayer	I-Application
is	O
considered	O
by	O
some	O
an	O
early	O
forerunner	O
of	O
the	O
modern	O
first-person	O
shooter	O
genre	O
.	O
</s>
<s>
The	O
player	O
moves	O
around	O
a	O
randomly	O
generated	O
maze	B-Application
,	O
attempting	O
to	O
kill	O
the	O
eponymous	O
phantoms	O
by	O
shooting	O
them	O
.	O
</s>
<s>
As	O
each	O
level	O
is	O
cleared	O
,	O
a	O
new	O
maze	B-Application
is	O
created	O
,	O
and	O
the	O
phantoms	O
became	O
harder	O
(	O
requiring	O
more	O
shots	O
)	O
to	O
kill	O
.	O
</s>
<s>
As	O
the	O
player	O
moves	O
around	O
the	O
maze	B-Application
,	O
the	O
only	O
indication	O
that	O
a	O
phantom	O
is	O
encroaching	O
is	O
an	O
ominous	O
sound	O
played	O
when	O
the	O
phantom	O
is	O
a	O
few	O
squares	O
away	O
from	O
the	O
player	O
's	O
position	O
.	O
</s>
