<s>
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
is	O
a	O
team-based	O
online	O
first-person	O
shooter	O
multiplayer	O
video	O
game	O
developed	O
by	O
Valve	O
.	O
</s>
<s>
Set	O
in	O
World	O
War	O
II	O
,	O
the	O
game	O
is	O
a	O
remake	B-General_Concept
of	O
Day	B-Application
of	I-Application
Defeat	I-Application
.	O
</s>
<s>
It	O
was	O
updated	O
from	O
the	O
GoldSrc	B-Application
engine	I-Application
used	O
by	O
its	O
predecessor	O
to	O
the	O
Source	B-Application
engine	I-Application
,	O
and	O
a	O
remake	B-General_Concept
of	O
the	O
game	O
models	O
.	O
</s>
<s>
The	O
game	O
was	O
released	O
for	O
Microsoft	B-Application
Windows	I-Application
on	O
September	O
26	O
,	O
2005	O
,	O
distributed	O
through	O
Valve	O
's	O
online	O
content	O
delivery	O
service	O
Steam	B-Application
.	O
</s>
<s>
During	O
the	O
course	O
of	O
its	O
development	O
,	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
progressed	O
from	O
being	O
a	O
straight	O
conversion	O
of	O
Day	B-Application
of	I-Application
Defeat	I-Application
,	O
to	O
the	O
alteration	O
of	O
certain	O
aspects	O
of	O
the	O
game	O
's	O
design	O
and	O
introduction	O
of	O
several	O
features	O
.	O
</s>
<s>
In	O
addition	O
,	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
has	O
been	O
used	O
by	O
Valve	O
to	O
present	O
new	O
design	O
features	O
on	O
the	O
Source	B-Application
engine	I-Application
,	O
such	O
as	O
high	B-Device
dynamic	I-Device
range	I-Device
rendering	I-Device
and	O
cinematic	O
effects	O
.	O
</s>
<s>
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
is	O
set	O
in	O
World	O
War	O
II	O
,	O
specifically	O
the	O
European	O
Theatre	O
in	O
1944	O
.	O
</s>
<s>
Day	B-Application
of	I-Application
Defeat:Source	I-Application
,	O
like	O
other	O
titles	O
developed	O
by	O
Valve	O
,	O
tracks	O
detailed	O
statistics	O
for	O
individual	O
players	O
.	O
</s>
<s>
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
features	O
numerous	O
"	O
achievements	O
"	O
for	O
carrying	O
out	O
certain	O
tasks	O
,	O
such	O
as	O
scoring	O
a	O
certain	O
number	O
of	O
kills	O
with	O
a	O
particular	O
weapon	O
or	O
completing	O
a	O
round	O
within	O
a	O
certain	O
time	O
.	O
</s>
<s>
Achievements	O
unlocked	O
and	O
statistics	O
from	O
previously	O
played	O
games	O
are	O
displayed	O
on	O
the	O
player	O
's	O
Steam	B-Application
profile	O
page	O
.	O
</s>
<s>
There	O
are	O
two	O
main	O
game	O
modes	O
in	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
:	O
territorial	O
control	O
and	O
detonation	O
.	O
</s>
<s>
Both	O
factions	O
in	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
have	O
access	O
to	O
six	O
classes	O
.	O
</s>
<s>
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
was	O
first	O
announced	O
for	O
Microsoft	B-Application
Windows	I-Application
during	O
the	O
development	O
of	O
Half-Life	B-Application
2	I-Application
,	O
the	O
flagship	O
game	O
of	O
the	O
Source	B-Application
engine	I-Application
,	O
as	O
one	O
of	O
several	O
of	O
the	O
Valve	O
's	O
GoldSrc	B-Application
powered	O
games	O
to	O
be	O
remade	O
on	O
the	O
new	O
game	O
engine	O
.	O
</s>
<s>
In	O
the	O
aftermath	O
of	O
the	O
release	O
of	O
Half-Life	B-Application
2	I-Application
and	O
Counter-Strike	B-Application
:	I-Application
Source	I-Application
,	O
very	O
little	O
information	O
was	O
released	O
regarding	O
the	O
development	O
of	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
until	O
2005	O
.	O
</s>
<s>
In	O
February	O
2005	O
,	O
Valve	O
announced	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
,	O
stating	O
that	O
the	O
game	O
was	O
nearing	O
its	O
beta	O
development	O
phase	O
and	O
would	O
be	O
available	O
later	O
in	O
the	O
first	O
quarter	O
of	O
the	O
year	O
.	O
</s>
<s>
The	O
game	O
was	O
opened	O
to	O
an	O
internal	O
beta	O
test	O
soon	O
after	O
,	O
which	O
certain	O
members	O
of	O
the	O
Day	B-Application
of	I-Application
Defeat	I-Application
community	O
were	O
invited	O
to	O
join	O
.	O
</s>
<s>
The	O
beta	O
version	O
of	O
the	O
game	O
was	O
shown	O
as	O
a	O
straight	O
conversion	O
of	O
the	O
most	O
recent	O
version	O
of	O
Day	B-Application
of	I-Application
Defeat	I-Application
,	O
at	O
the	O
time	O
even	O
including	O
the	O
same	O
player	O
and	O
weapon	O
models	O
as	O
the	O
game	O
's	O
GoldSrc	B-Application
counterpart	O
.	O
</s>
<s>
Due	O
to	O
the	O
response	O
of	O
the	O
beta	O
testers	O
,	O
significant	O
changes	O
were	O
made	O
to	O
the	O
gameplay	O
,	O
taking	O
it	O
away	O
from	O
being	O
a	O
straight	O
conversion	O
:	O
the	O
behaviour	O
of	O
weapons	O
was	O
altered	O
and	O
several	O
classes	O
from	O
Day	B-Application
of	I-Application
Defeat	I-Application
were	O
dropped	O
entirely	O
.	O
</s>
<s>
The	O
game	O
was	O
made	O
available	O
for	O
preload	O
via	O
Valve	O
's	O
Steam	B-Application
content	I-Application
delivery	I-Application
system	O
on	O
September	O
14	O
,	O
2005	O
,	O
and	O
was	O
officially	O
released	O
on	O
time	O
on	O
September	O
26	O
.	O
</s>
<s>
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
has	O
undergone	O
several	O
updates	O
.	O
</s>
<s>
The	O
first	O
new	O
level	O
was	O
released	O
on	O
November	O
30	O
,	O
2005	O
,	O
and	O
was	O
followed	O
on	O
January	O
25	O
,	O
2006	O
by	O
another	O
map	O
,	O
used	O
as	O
a	O
demonstration	O
for	O
the	O
Source	B-Application
engine	I-Application
's	O
abilities	O
in	O
rendering	O
snow	O
and	O
ice	O
.	O
</s>
<s>
On	O
May	O
23	O
,	O
2008	O
,	O
Valve	O
announced	O
another	O
major	O
update	O
to	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
,	O
this	O
time	O
giving	O
the	O
game	O
support	O
for	O
the	O
company	O
's	O
new	O
Steamworks	O
programmer	O
.	O
</s>
<s>
The	O
update	O
is	O
open	O
to	O
any	O
owners	O
of	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
.	O
</s>
<s>
Along	O
with	O
various	O
gameplay	O
tweaks	O
,	O
the	O
update	O
moves	O
the	O
game	O
to	O
the	O
Source	B-Application
engine	I-Application
version	O
used	O
with	O
The	B-Application
Orange	I-Application
Box	I-Application
,	O
allowing	O
the	O
game	O
to	O
utilize	O
particle	O
effects	O
,	O
as	O
well	O
as	O
adding	O
a	O
map	O
based	O
on	O
a	O
long-standing	O
custom	O
map	O
for	O
Day	B-Application
of	I-Application
Defeat	I-Application
and	O
54	O
achievement	O
awards	O
for	O
players	O
completing	O
certain	O
tasks	O
.	O
</s>
<s>
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
has	O
been	O
used	O
by	O
Valve	O
as	O
a	O
platform	O
for	O
demonstrating	O
several	O
technologies	O
in	O
the	O
Source	B-Application
engine	I-Application
.	O
</s>
<s>
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
introduced	O
a	O
dynamic	O
audio	O
system	O
that	O
was	O
limited	O
to	O
non-player	O
characters	O
in	O
Half-Life	B-Application
2	I-Application
.	O
</s>
<s>
The	O
game	O
was	O
the	O
first	O
to	O
incorporate	O
Valve	O
's	O
high	B-Device
dynamic	I-Device
range	I-Device
rendering	I-Device
,	O
predating	O
the	O
official	O
demonstration	O
,	O
Half-Life	B-Application
2	I-Application
:	I-Application
Lost	I-Application
Coast	I-Application
.	O
</s>
<s>
Phong	O
shading	O
on	O
the	O
Source	B-Application
engine	I-Application
was	O
added	O
to	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
with	O
the	O
major	O
update	O
in	O
the	O
second	O
quarter	O
of	O
2006	O
.	O
</s>
<s>
To	O
convey	O
this	O
effect	O
,	O
the	O
trailers	O
make	O
extensive	O
usage	O
of	O
the	O
Source	B-Application
engine	I-Application
's	O
capabilities	O
for	O
film	O
grain	O
,	O
color	O
correction	O
,	O
motion	O
blur	O
and	O
depth	O
of	O
field	O
,	O
as	O
well	O
as	O
sepia	O
toning	O
.	O
</s>
<s>
Two	O
further	O
trailers	O
were	O
released	O
to	O
promote	O
the	O
major	O
update	O
to	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
in	O
the	O
second	O
quarter	O
of	O
2006	O
.	O
</s>
<s>
To	O
further	O
create	O
interest	O
in	O
the	O
game	O
,	O
Valve	O
has	O
opened	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
to	O
three	O
free	O
weekends	O
,	O
the	O
first	O
taking	O
place	O
on	O
February	O
10	O
,	O
2006	O
,	O
the	O
second	O
on	O
July	O
8	O
,	O
2006	O
and	O
the	O
third	O
on	O
July	O
4	O
,	O
2008	O
,	O
where	O
anyone	O
with	O
a	O
Steam	B-Application
account	O
could	O
download	O
and	O
play	O
the	O
game	O
for	O
a	O
maximum	O
of	O
48	O
hours	O
free	O
of	O
charge	O
.	O
</s>
<s>
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
was	O
given	O
a	O
positive	O
reception	O
,	O
receiving	O
ratings	O
of	O
80/100	O
and	O
81%	O
from	O
the	O
review	O
aggregation	O
sites	O
Metacritic	O
and	O
GameRankings	O
.	O
</s>
<s>
The	O
game	O
's	O
graphics	O
received	O
praise	O
,	O
with	O
GameSpot	O
stating	O
that	O
"	O
presentation	O
is	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	O
Sources	O
most	O
obvious	O
strength	O
"	O
,	O
and	O
PC	O
Zone	O
citing	O
this	O
for	O
creating	O
a	O
"	O
tense	O
and	O
atmospheric	O
"	O
game	O
.	O
</s>
<s>
In	O
addition	O
,	O
PC	O
Zone	O
commented	O
that	O
"	O
by	O
still	O
clinging	O
to	O
the	O
small-scale	O
skirmish	O
atmosphere	O
of	O
the	O
original	O
,	O
Day	B-Application
of	I-Application
Defeat	I-Application
:	I-Application
Source	I-Application
does	O
n't	O
make	O
much	O
of	O
departure	O
from	O
Counter-Strike	B-Application
"	O
,	O
stating	O
that	O
this	O
made	O
the	O
game	O
seem	O
like	O
a	O
"	O
facelift	O
"	O
to	O
a	O
"	O
much-loved	O
mod	O
 [ ... ] 	O
before	O
making	O
us	O
pay	O
for	O
it	O
again	O
"	O
.	O
</s>
