<s>
Duke	B-Application
Nukem	I-Application
is	O
a	O
1991	O
platform	O
game	O
developed	O
and	O
published	O
by	O
Apogee	O
Software	O
for	O
MS-DOS	B-Application
.	O
</s>
<s>
The	O
2D	O
,	O
multidirectional	O
scrolling	O
game	O
follows	O
the	O
adventures	O
of	O
fictional	O
character	O
Duke	B-Application
Nukem	I-Application
across	O
three	O
episodes	O
of	O
ten	O
levels	O
each	O
.	O
</s>
<s>
The	O
name	O
was	O
briefly	O
changed	O
to	O
Duke	B-Application
Nukum	I-Application
to	O
avoid	O
copyright	O
issues	O
.	O
</s>
<s>
Duke	B-Application
Nukem	I-Application
was	O
followed	O
by	O
the	O
similarly-styled	O
Duke	B-Application
Nukem	I-Application
II	I-Application
,	O
in	O
1993	O
.	O
</s>
<s>
The	O
series	O
made	O
the	O
jump	O
to	O
3D	O
graphics	O
with	O
Duke	B-Application
Nukem	I-Application
3D	I-Application
in	O
1996	O
,	O
which	O
became	O
the	O
most	O
popular	O
of	O
the	O
three	O
games	O
.	O
</s>
<s>
Duke	B-Application
Nukem	I-Application
,	O
the	O
eponymous	O
hero	O
,	O
takes	O
upon	O
the	O
task	O
of	O
stopping	O
him	O
.	O
</s>
<s>
According	O
to	O
programmer	O
and	O
co-creator	O
Todd	O
Replogle	O
,	O
John	O
Carmack	O
helped	O
him	O
program	O
some	O
low-level	O
parts	O
of	O
the	O
game	O
code	O
in	O
assembly	B-Language
language	I-Language
.	O
</s>
<s>
After	O
the	O
game	O
's	O
release	O
,	O
Apogee	O
Software	O
became	O
aware	O
that	O
the	O
Captain	B-Application
Planet	I-Application
and	I-Application
the	I-Application
Planeteers	I-Application
animated	O
series	O
featured	O
a	O
character	O
with	O
the	O
same	O
name	O
(	O
Duke	B-Application
Nukem	I-Application
)	O
and	O
therefore	O
to	O
avoid	O
a	O
lawsuit	O
,	O
the	O
software	O
house	O
renamed	O
the	O
2.0	O
version	O
of	O
its	O
game	O
Duke	B-Application
Nukum	I-Application
.	O
</s>
<s>
It	O
later	O
turned	O
out	O
that	O
Duke	B-Application
Nukem	I-Application
was	O
not	O
a	O
registered	O
name	O
,	O
so	O
Apogee	O
registered	O
it	O
and	O
used	O
the	O
original	O
Duke	B-Application
Nukem	I-Application
name	O
in	O
the	O
sequels	O
.	O
</s>
<s>
Apogee	O
successfully	O
fought	O
back	O
,	O
and	O
agreed	O
to	O
use	O
the	O
full	O
Duke	B-Application
Nukem	I-Application
name	O
in	O
all	O
their	O
marketing	O
materials	O
.	O
</s>
<s>
A	O
free	B-Application
software	I-Application
remake	O
of	O
the	O
game	O
was	O
made	O
by	O
fans	O
entitled	O
Dave	O
Gnukem	O
.	O
</s>
