<s>
is	O
the	O
16th	O
game	O
in	O
the	O
Touhou	B-Application
Project	I-Application
series	O
.	O
</s>
<s>
The	O
game	O
was	O
released	O
on	O
Steam	B-Application
worldwide	O
on	O
November	O
17	O
,	O
2017	O
,	O
becoming	O
the	O
first	O
game	O
in	O
the	O
series	O
to	O
be	O
available	O
on	O
the	O
platform	O
.	O
</s>
<s>
Hidden	B-Application
Star	I-Application
in	I-Application
Four	I-Application
Seasons	I-Application
is	O
a	O
vertically	O
scrolling	O
shoot	O
'	O
em	O
up	O
game	O
,	O
in	O
which	O
the	O
player	O
is	O
always	O
facing	O
upwards	O
,	O
and	O
is	O
required	O
to	O
maneuver	O
around	O
enemy	O
projectiles	O
,	O
shooting	O
enemies	O
that	O
appear	O
from	O
the	O
top	O
of	O
the	O
screen	O
,	O
and	O
fighting	O
bosses	O
that	O
appear	O
twice	O
in	O
each	O
stage	O
.	O
</s>
<s>
Hidden	B-Application
Star	I-Application
in	I-Application
Four	I-Application
Seasons	I-Application
has	O
a	O
unique	O
mechanic	O
known	O
as	O
the	O
Season	O
Gauge	O
.	O
</s>
<s>
The	O
Hakurei	B-Application
Shrine	I-Application
is	O
showered	O
in	O
cherry	O
petals	O
,	O
Youkai	B-Application
Mountain	I-Application
is	O
basking	O
in	O
the	O
middle	O
of	O
autumn	O
,	O
and	O
the	O
Forest	O
of	O
Magic	O
is	O
blanketed	O
in	O
snow	O
,	O
and	O
thanks	O
to	O
some	O
strange	O
force	O
,	O
Gensokyo	O
's	O
fairies	O
are	O
running	O
rampant	O
with	O
unfathomable	O
strength	O
.	O
</s>
