<s>
Earth	B-Application
Defense	I-Application
(	O
)	O
,	O
credited	O
as	O
The	O
Earth	O
Defend	O
on	O
title	O
screen	O
,	O
is	O
an	O
unlicensed	O
game	O
for	O
the	O
Sega	B-Operating_System
Mega	I-Operating_System
Drive/Genesis	I-Operating_System
;	O
it	O
was	O
developed	O
by	O
AV	O
Artisan	O
and	O
published	O
by	O
Realtec	O
in	O
both	O
North	O
America	O
and	O
Taiwan	O
,	O
without	O
a	O
license	O
from	O
Sega	O
.	O
</s>
<s>
Earth	B-Application
Defense	I-Application
was	O
also	O
rare	O
in	O
that	O
it	O
was	O
a	O
simultaneous	O
2	O
player	O
vertical	O
scrolling	O
shoot	O
'	O
em	O
up	O
on	O
the	O
Genesis	O
which	O
primarily	O
featured	O
single	O
player	O
shoot	O
'	O
em	O
ups	O
.	O
</s>
<s>
The	O
game	O
cannot	O
be	O
played	O
through	O
a	O
Sega	B-Device
32X	I-Device
.	O
</s>
<s>
The	O
game	O
must	O
be	O
put	O
directly	O
into	O
the	O
Sega	B-Operating_System
Genesis	I-Operating_System
 '	O
cartridge	O
slot	O
.	O
</s>
<s>
When	O
the	O
game	O
is	O
inserted	O
into	O
a	O
Sega	B-Device
32X	I-Device
,	O
the	O
RealTec	O
logo	O
will	O
show	O
up	O
,	O
but	O
the	O
Sega	B-Operating_System
Genesis	I-Operating_System
will	O
keep	O
resetting	O
itself	O
.	O
</s>
<s>
The	O
game	O
will	O
not	O
run	O
at	O
all	O
on	O
the	O
Majesco	O
Sega	B-Operating_System
Genesis	I-Operating_System
3	O
.	O
</s>
