<s>
Sonic	B-Application
Riders	I-Application
:	I-Application
Zero	I-Application
Gravity	I-Application
is	O
a	O
hoverboard	O
racing	O
video	O
game	O
developed	O
by	O
Sonic	B-Application
Team	O
and	O
published	O
by	O
Sega	O
for	O
the	O
PlayStation	B-Device
2	I-Device
and	O
Wii	B-Operating_System
.	O
</s>
<s>
It	O
is	O
the	O
fifth	O
pure	O
racing	O
game	O
in	O
the	O
Sonic	B-Application
the	I-Application
Hedgehog	I-Application
series	I-Application
,	O
and	O
the	O
second	O
entry	O
in	O
the	O
Sonic	B-Application
Riders	I-Application
trilogy	O
,	O
a	O
spin-off	O
of	O
the	O
main	O
series	O
.	O
</s>
<s>
A	O
sequel	O
,	O
Sonic	B-Application
Free	I-Application
Riders	I-Application
,	O
was	O
released	O
for	O
the	O
Xbox	O
360	O
in	O
2010	O
.	O
</s>
<s>
Gameplay	O
in	O
Zero	B-Application
Gravity	I-Application
is	O
largely	O
similar	O
to	O
its	O
predecessor	O
,	O
with	O
characters	O
racing	O
on	O
different	O
types	O
of	O
hovercraft	O
called	O
"	O
Extreme	B-Application
Gear	I-Application
"	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
mechanics	O
from	O
the	O
previous	O
game	O
,	O
Zero	B-Application
Gravity	I-Application
adds	O
a	O
new	O
gameplay	O
system	O
based	O
around	O
gravity	O
that	O
replaces	O
the	O
predecessor	O
's	O
"	O
fuel	O
"	O
system	O
.	O
</s>
<s>
A	O
Gravity	O
Dive	O
will	O
create	O
a	O
small	O
black	B-Application
hole	I-Application
that	O
points	O
gravity	O
forward	O
down	O
the	O
track	O
,	O
giving	O
the	O
player	O
a	O
powerful	O
free-fall	O
boost	O
that	O
is	O
further	O
augmented	O
by	O
striking	O
objects	O
in	O
the	O
vicinity	O
that	O
the	O
hole	O
displaces	O
,	O
such	O
as	O
cars	O
or	O
signs	O
.	O
</s>
<s>
Building	O
on	O
the	O
upgrade	O
system	O
from	O
Sonic	B-Application
Riders	I-Application
,	O
Zero	B-Application
Gravity	I-Application
features	O
a	O
new	O
system	O
called	O
"	O
Gear	O
Change	O
"	O
.	O
</s>
<s>
Gear	O
Parts	O
are	O
predetermined	O
based	O
on	O
the	O
racer	O
's	O
equipped	O
Extreme	B-Application
Gear	I-Application
,	O
and	O
will	O
grant	O
bonuses	O
when	O
activated	O
,	O
such	O
as	O
increasing	O
a	O
character	O
's	O
top	O
speed	O
or	O
automatically	O
accessing	O
shortcuts	O
that	O
would	O
otherwise	O
require	O
Gravity	O
Control	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
boards	O
,	O
skates	O
,	O
and	O
bikes	O
from	O
the	O
previous	O
game	O
,	O
Zero	B-Application
Gravity	I-Application
also	O
introduces	O
three	O
new	O
types	O
of	O
Extreme	B-Application
Gear	I-Application
:	O
air	O
rides	O
,	O
yachts	O
,	O
and	O
wheels	O
.	O
</s>
<s>
New	O
Extreme	B-Application
Gear	I-Application
can	O
be	O
unlocked	O
via	O
the	O
in-game	O
shop	O
,	O
with	O
different	O
Gear	O
providing	O
different	O
advantages	O
and	O
unique	O
abilities	O
.	O
</s>
<s>
A	O
total	O
of	O
18	O
playable	O
characters	O
can	O
be	O
unlocked	O
,	O
including	O
guest	O
characters	O
from	O
Billy	B-Application
Hatcher	I-Application
and	I-Application
the	I-Application
Giant	I-Application
Egg	I-Application
,	O
Nights	B-Application
into	I-Application
Dreams	I-Application
,	O
and	O
Samba	B-Application
de	I-Application
Amigo	I-Application
.	O
</s>
<s>
Zero	B-Application
Gravity	I-Application
once	O
again	O
features	O
two	O
story	O
campaigns	O
,	O
"	O
Heroes	O
"	O
and	O
"	O
Babylon	O
"	O
,	O
which	O
intersect	O
with	O
one	O
another	O
to	O
create	O
a	O
single	O
narrative	O
.	O
</s>
<s>
In	O
Survival	O
Relay	O
,	O
teams	O
of	O
two	O
compete	O
in	O
a	O
relay	O
race	O
,	O
using	O
their	O
Extreme	B-Application
Gear	I-Application
as	O
the	O
baton	O
.	O
</s>
<s>
The	B-Operating_System
Wii	I-Operating_System
version	O
supports	O
two	O
different	O
Wii	B-Device
Remote	I-Device
control	O
schemes	O
,	O
which	O
utilize	O
motion	O
controls	O
to	O
steer	O
and	O
perform	O
Gravity	O
Dives	O
;	O
traditional	O
controls	O
are	O
also	O
available	O
via	O
the	O
use	O
of	O
the	O
Nintendo	B-Device
GameCube	I-Device
controller	I-Device
.	O
</s>
<s>
Sonic	B-Application
,	O
who	O
is	O
traveling	O
with	O
Tails	O
and	O
Knuckles	O
,	O
finds	O
one	O
of	O
the	O
Arks	O
.	O
</s>
<s>
Sonic	B-Application
and	O
the	O
others	O
retrieve	O
Amy	O
and	O
travel	O
to	O
Crimson	O
Tower	O
to	O
shut	O
down	O
the	O
mother	O
computer	O
.	O
</s>
<s>
They	O
meet	O
the	O
Rogues	O
there	O
,	O
and	O
Jet	O
challenges	O
Sonic	B-Application
to	O
one	O
last	O
race	O
,	O
with	O
the	O
winner	O
getting	O
all	O
the	O
Arks	O
.	O
</s>
<s>
The	O
Arks	O
 '	O
resonance	O
calls	O
down	O
the	O
Babylon	O
Garden	O
,	O
and	O
Sonic	B-Application
hands	O
his	O
Arks	O
over	O
to	O
Jet	O
.	O
</s>
<s>
SCR-HD	O
activates	O
the	O
Arks	O
,	O
revealing	O
an	O
ancient	O
spaceship	O
inside	O
Babylon	O
Garden	O
,	O
creating	O
a	O
massive	O
black	B-Application
hole	I-Application
capable	O
of	O
destroying	O
the	O
planet	O
and	O
transforming	O
into	O
a	O
monstrous	O
robot	O
named	O
Master	O
Core	O
ABIS	O
.	O
</s>
<s>
Eggman	O
escapes	O
while	O
the	O
heroes	O
and	O
Rogues	O
head	O
for	O
the	O
ship	O
and	O
defeat	O
ABIS	O
with	O
Gravity	O
Dives	O
,	O
shutting	O
down	O
the	O
Arks	O
and	O
stopping	O
the	O
black	B-Application
hole	I-Application
,	O
leaving	O
the	O
ship	O
adrift	O
in	O
orbit	O
.	O
</s>
<s>
Jet	O
arrives	O
and	O
challenges	O
Sonic	B-Application
,	O
who	O
happily	O
accepts	O
.	O
</s>
<s>
Zero	B-Application
Gravity	I-Application
received	O
mixed	O
reviews	O
from	O
critics	O
.	O
</s>
<s>
Aggregating	O
review	O
websites	O
GameRankings	O
and	O
Metacritic	O
assigned	O
the	O
PlayStation	B-Device
2	I-Device
version	O
59.31	O
%	O
and	O
56/100	O
and	O
the	B-Operating_System
Wii	I-Operating_System
version	O
57.04	O
%	O
and	O
56/100	O
.	O
</s>
<s>
GameSpot	O
gave	O
the	O
PS2	B-Device
version	O
5.0/10	O
and	O
the	B-Operating_System
Wii	I-Operating_System
version	O
4.5/10	O
.	O
</s>
<s>
IGN	O
rated	O
both	O
the	O
PS2	B-Device
and	O
the	B-Operating_System
Wii	I-Operating_System
versions	O
a	O
5.8/10	O
.	O
</s>
<s>
GameTrailers	O
praised	O
the	O
game	O
for	O
its	O
graphics	O
,	O
but	O
criticized	O
how	O
the	O
game	O
required	O
the	O
GameCube	B-Device
controller	I-Device
for	O
traditional	O
control	O
,	O
which	O
would	O
be	O
unavailable	O
when	O
played	O
on	O
newer	O
Wii	B-Operating_System
models	O
or	O
the	B-Operating_System
Wii	I-Operating_System
U	O
,	O
as	O
well	O
as	O
how	O
the	O
game	O
could	O
be	O
"	O
almost	O
unplayable	O
"	O
with	O
confusing	O
option	O
selections	O
.	O
</s>
<s>
Game	O
Informer	O
gave	O
the	O
game	O
an	O
overall	O
score	O
of	O
6	O
out	O
of	O
10	O
criticizing	O
the	B-Operating_System
Wii	I-Operating_System
motion	O
control	O
making	O
the	O
game	O
needlessly	O
frustrating	O
and	O
even	O
using	O
a	O
GameCube	B-Device
controller	I-Device
the	O
game	O
is	O
nearly	O
mediocre	O
.	O
</s>
