<s>
Sonic	B-Application
the	I-Application
Hedgehog	I-Application
is	O
a	O
video	O
game	O
series	O
.	O
</s>
<s>
It	O
is	O
published	O
by	O
Sega	O
,	O
with	O
entries	O
developed	O
by	O
Sega	O
,	O
Sonic	B-Application
Team	O
,	O
Dimps	O
,	O
SIMS	O
Co.	O
,	O
Ltd.	O
,	O
BioWare	O
,	O
and	O
Sumo	O
Digital	O
.	O
</s>
<s>
The	O
series	O
debuted	O
in	O
1991	O
with	O
the	O
video	O
game	O
,	O
Sonic	B-Application
the	I-Application
Hedgehog	I-Application
,	O
released	O
for	O
the	O
Mega	B-Operating_System
Drive	I-Operating_System
video	B-Device
game	I-Device
console	I-Device
(	O
named	O
Sega	B-Operating_System
Genesis	I-Operating_System
in	O
North	O
America	O
)	O
.	O
</s>
<s>
In	O
its	O
earliest	O
history	O
,	O
most	O
Sonic	B-Application
the	I-Application
Hedgehog	I-Application
games	O
had	O
been	O
platform	O
games	O
released	O
for	O
Sega	O
video	B-Device
game	I-Device
consoles	I-Device
and	O
handheld	B-Application
game	I-Application
consoles	I-Application
(	O
handhelds	B-Application
)	O
,	O
dating	O
from	O
the	O
Sega	B-Operating_System
Genesis	I-Operating_System
to	O
the	O
Sega	B-Operating_System
Dreamcast	I-Operating_System
.	O
</s>
<s>
The	O
most	O
popular	O
games	O
in	O
the	O
franchise	O
are	O
platform	O
games	O
,	O
although	O
the	O
series	O
also	O
includes	O
other	O
genres	O
such	O
as	O
racing	O
video	O
games	O
,	O
fighting	O
games	O
,	O
action-adventure	O
games	O
,	O
role-playing	O
video	O
games	O
,	O
and	O
sports	O
games	O
.	O
</s>
<s>
Each	O
game	O
focuses	O
on	O
the	O
titular	O
protagonist	O
Sonic	B-Application
the	I-Application
Hedgehog	I-Application
,	O
an	O
anthropomorphic	O
blue	O
hedgehog	O
.	O
</s>
<s>
It	O
also	O
features	O
a	O
large	O
cast	O
of	O
other	O
characters	O
such	O
as	O
Doctor	O
Ivo	O
"	O
Eggman	O
"	O
Robotnik	O
,	O
Miles	O
"	O
Tails	O
"	O
Prower	O
,	O
Knuckles	O
the	O
Echidna	O
,	O
Amy	O
Rose	O
,	O
Shadow	B-Application
the	I-Application
Hedgehog	I-Application
,	O
and	O
the	O
Chao	O
creatures	O
.	O
</s>
