<s>
is	O
a	O
shoot	O
'	O
em	O
up	O
video	O
game	O
developed	O
by	O
Irem	O
and	O
released	O
for	O
the	O
PlayStation	B-Device
console	I-Device
in	O
1998	O
.	O
</s>
<s>
It	O
is	O
the	O
fourth	O
game	O
in	O
the	O
R-Type	B-Application
series	O
and	O
the	O
first	O
to	O
feature	O
3D	O
graphics	O
.	O
</s>
<s>
R-Type	B-Application
Delta	I-Application
is	O
a	O
shoot	O
'	O
em	O
up	O
set	O
in	O
2164	O
.	O
</s>
<s>
Irem	O
began	O
development	O
of	O
R-Type	B-Application
Delta	I-Application
in	O
early	O
1998	O
.	O
</s>
<s>
Around	O
the	O
beginning	O
of	O
its	O
development	O
,	O
Taito	O
released	O
a	O
conversion	O
of	O
their	O
arcade	O
game	O
RayStorm	B-Application
for	O
the	O
PlayStation	B-Device
,	O
whose	O
3D	O
visuals	O
caught	O
the	O
eye	O
of	O
several	O
video	O
game	O
developers	O
and	O
led	O
to	O
the	O
release	O
of	O
several	O
3D	O
shooting	O
games	O
for	O
the	O
console	O
.	O
</s>
<s>
Being	O
rather	O
impressed	O
with	O
its	O
fast-paced	O
action	O
and	O
polygonal	O
graphics	O
,	O
Irem	O
began	O
to	O
create	O
a	O
new	O
R-Type	B-Application
game	O
that	O
could	O
potentially	O
rival	O
the	O
success	O
of	O
Taito	O
's	O
game	O
.	O
</s>
<s>
The	O
goal	O
of	O
the	O
playable	O
ships	O
idea	O
was	O
for	O
each	O
of	O
them	O
to	O
be	O
distinctively	O
different	O
from	O
one	O
another	O
without	O
disrupting	O
the	O
core	O
R-Type	B-Application
gameplay	O
,	O
to	O
make	O
it	O
feel	O
like	O
the	O
player	O
was	O
playing	O
an	O
entirely	O
new	O
game	O
with	O
each	O
ship	O
.	O
</s>
<s>
The	O
R-9	O
from	O
the	O
original	O
R-Type	B-Application
was	O
chosen	O
at	O
the	O
very	O
start	O
,	O
followed	O
by	O
an	O
updated	O
version	O
named	O
the	O
R-X	O
.	O
</s>
<s>
Kita	O
came	O
up	O
with	O
the	O
name	O
R-Type	B-Application
Delta	I-Application
based	O
on	O
the	O
fact	O
three	O
different	O
ships	O
were	O
playable	O
,	O
which	O
reminded	O
him	O
of	O
the	O
Greek	O
symbol	O
delta	O
.	O
</s>
<s>
Early	O
planning	O
documents	O
for	O
the	O
game	O
referred	O
to	O
it	O
as	O
R-Type	B-Application
EVE	O
,	O
a	O
titled	O
named	O
after	O
the	O
novel	O
Parasite	O
Eve	O
and	O
met	O
with	O
a	O
mixture	O
of	O
confusion	O
from	O
the	O
production	O
team	O
.	O
</s>
<s>
Other	O
members	O
suggested	O
R-Type	B-Application
IV	I-Application
or	O
simply	O
R-Type	B-Application
,	O
which	O
they	O
argued	O
made	O
it	O
more	O
recognizable	O
.	O
</s>
<s>
He	O
also	O
said	O
the	O
symbol	O
represented	O
the	O
number	O
4	O
,	O
which	O
alluded	O
to	O
it	O
being	O
the	O
fourth	O
mainline	O
R-Type	B-Application
game	O
.	O
</s>
<s>
The	O
difficulty	O
itself	O
was	O
made	O
much	O
harder	O
than	O
previous	O
R-Type	B-Application
games	O
as	O
the	O
team	O
wanted	O
the	O
player	O
to	O
memorize	O
stage	O
patterns	O
and	O
learn	O
from	O
their	O
mistakes	O
,	O
which	O
they	O
claimed	O
made	O
the	O
game	O
much	O
more	O
worthwhile	O
to	O
play	O
.	O
</s>
<s>
R-Type	B-Application
Delta	I-Application
received	O
positive	O
reviews	O
from	O
critics	O
,	O
who	O
generally	O
praised	O
its	O
addictive	O
gameplay	O
and	O
detailed	O
graphics	O
.	O
</s>
<s>
Electronic	O
Gaming	O
Monthly	O
reviewer	O
Che	O
Chou	O
described	O
the	O
game	O
as	O
"	O
the	O
best	O
R-Type	B-Application
 [ title ] 	O
ever	O
"	O
,	O
while	O
Peter	O
Bartholow	O
of	O
GameSpot	O
commented	O
,	O
"	O
If	O
there	O
's	O
one	O
PlayStation	B-Device
shooter	O
to	O
own	O
,	O
R-Type	B-Application
Delta	I-Application
is	O
that	O
shooter.	O
"	O
</s>
<s>
The	O
game	O
's	O
graphics	O
were	O
highlighted	O
for	O
their	O
diversity	O
,	O
colors	O
,	O
details	O
,	O
and	O
complex	O
polygon	B-General_Concept
models	O
,	O
with	O
GameSpot	O
noting	O
that	O
each	O
enemy	O
offers	O
unique	O
explosions	O
and	O
attacks	O
.	O
</s>
<s>
Tom	O
Russo	O
reviewed	O
the	O
PlayStation	B-Device
version	O
of	O
the	O
game	O
for	O
Next	O
Generation	O
,	O
rating	O
it	O
three	O
stars	O
out	O
of	O
five	O
,	O
and	O
stated	O
that	O
"	O
Overall	O
,	O
a	O
fantastic	O
looking	O
effort	O
,	O
but	O
proof	O
that	O
the	O
gameplay	O
limits	O
of	O
this	O
genre	O
will	O
soon	O
relegate	O
all	O
2D	O
shooters	O
to	O
classic	O
collections.	O
"	O
</s>
<s>
In	O
2015	O
,	O
Hardcore	O
Gamer	O
included	O
R-Type	B-Application
Delta	I-Application
on	O
their	O
200	O
Best	O
Video	O
Games	O
of	O
All	O
Time	O
.	O
</s>
