<s>
is	O
a	O
vertically	O
scrolling	O
shooter	O
maze	B-Application
game	I-Application
released	O
by	O
Sega	O
as	O
an	O
arcade	B-Application
video	I-Application
game	I-Application
in	O
April	O
1981	B-Application
.	O
</s>
<s>
In	O
the	O
second	O
stage	O
,	O
the	O
player	O
maneuvers	O
his	O
Jeep	O
through	O
underbrush	O
,	O
and	O
enemies	O
can	O
only	O
follow	O
on	O
its	O
path	O
,	O
a	O
concept	O
later	O
found	O
in	O
Namco	O
's	O
Dig	B-Application
Dug	I-Application
(	O
1982	O
)	O
.	O
</s>
<s>
Borderline	B-Application
was	O
reissued	O
later	O
in	O
the	O
year	O
with	O
slightly	O
altered	O
graphics	O
as	O
Star	O
Raker	O
.	O
</s>
<s>
Borderline	B-Application
was	O
a	O
launch	O
game	O
for	O
the	O
SG-1000	B-Operating_System
in	O
1983	O
.	O
</s>
<s>
It	O
was	O
converted	O
for	O
the	O
Atari	B-General_Concept
2600	I-General_Concept
under	O
the	O
name	O
Thunderground	O
,	O
released	O
by	O
Sega	O
's	O
home	O
division	O
;	O
it	O
was	O
one	O
of	O
the	O
last	O
games	O
Sega	O
released	O
as	O
a	O
third-party	O
developer	O
for	O
Atari	O
.	O
</s>
<s>
The	O
SG-1000	B-Operating_System
and	O
Atari	B-General_Concept
2600	I-General_Concept
ports	O
received	O
positive	O
reviews	O
from	O
critics	O
.	O
</s>
<s>
Meade	O
and	O
Jim	O
Clark	O
of	O
Videogaming	O
Illustrated	O
magazine	O
reviewed	O
the	O
Atari	B-General_Concept
2600	I-General_Concept
version	O
Thunderground	O
in	O
1983	O
.	O
</s>
<s>
Despite	O
the	O
original	O
Borderline	B-Application
predating	O
Dig	B-Application
Dug	I-Application
and	O
Mr.	B-Application
Do	I-Application
!	I-Application
</s>
<s>
(	O
1982	O
)	O
,	O
the	O
reviewers	O
were	O
under	O
the	O
impression	O
that	O
Thunderground	O
was	O
a	O
"	O
semi-clone	O
"	O
of	O
Dig	B-Application
Dug	I-Application
and	O
Mr.	B-Application
Do	I-Application
!	I-Application
</s>
<s>
Meade	O
gave	O
it	O
an	O
A	O
rating	O
;	O
she	O
said	O
"	O
there	O
are	O
superficial	O
similarities	O
to	O
Dig	B-Application
Dug	I-Application
and	O
Mr.	B-Application
Do	I-Application
"	O
but	O
Thunderground	O
"	O
is	O
a	O
semi-clone	O
with	O
muscle	O
!	O
"	O
</s>
<s>
French	O
magazine	O
Tilt	O
reviewed	O
the	O
SG-1000	B-Operating_System
version	O
of	O
Borderline	B-Application
in	O
1984	O
.	O
</s>
<s>
In	O
a	O
retrospective	O
review	O
of	O
the	O
SG-1000	B-Operating_System
version	O
in	O
2014	O
,	O
Sega	O
Does	O
gave	O
it	O
a	O
generally	O
favorable	O
review	O
with	O
a	O
B−	O
rating	O
.	O
</s>
