<s>
Half-Life	B-Application
:	I-Application
Blue	I-Application
Shift	I-Application
is	O
an	O
expansion	O
pack	O
for	O
the	O
first-person	O
shooter	O
video	O
game	O
Half-Life	B-Application
(	O
1998	O
)	O
.	O
</s>
<s>
Blue	O
Shift	O
was	O
the	O
second	O
expansion	O
for	O
Half-Life	B-Application
,	O
originally	O
intended	O
as	O
part	O
of	O
a	O
Dreamcast	B-Operating_System
port	O
of	O
Half-Life	B-Application
.	O
</s>
<s>
Although	O
the	B-Operating_System
Dreamcast	I-Operating_System
port	O
was	O
cancelled	O
,	O
the	O
Windows	B-Application
version	O
was	O
released	O
as	O
a	O
standalone	O
product	O
on	O
June	O
12	O
,	O
2001	O
for	O
Windows	B-Application
.	O
</s>
<s>
It	O
was	O
released	O
on	O
Steam	B-Application
on	O
August	O
24	O
,	O
2005	O
.	O
</s>
<s>
As	O
with	O
Gearbox	O
's	O
previous	O
expansion	O
pack	O
,	O
Opposing	B-Application
Force	I-Application
(	O
1999	O
)	O
,	O
Blue	O
Shift	O
returns	O
to	O
the	O
setting	O
and	O
events	O
of	O
Half-Life	B-Application
,	O
but	O
portrays	O
the	O
story	O
through	O
the	O
eyes	O
of	O
another	O
character	O
.	O
</s>
<s>
Blue	O
Shift	O
also	O
includes	O
a	O
graphics	O
pack	O
that	O
upgrades	O
the	O
Half-Life	B-Application
models	O
and	O
textures	O
.	O
</s>
<s>
As	O
an	O
expansion	O
pack	O
for	O
Half-Life	B-Application
,	O
Blue	O
Shift	O
is	O
a	O
first-person	O
shooter	O
.	O
</s>
<s>
The	O
overall	O
gameplay	O
of	O
Blue	O
Shift	O
does	O
not	O
significantly	O
differ	O
from	O
that	O
of	O
Half-Life	B-Application
:	O
players	O
are	O
required	O
to	O
navigate	O
through	O
the	O
game	O
's	O
levels	O
,	O
fight	O
hostile	O
non-player	O
characters	O
and	O
solve	O
a	O
variety	O
of	O
puzzles	O
to	O
advance	O
.	O
</s>
<s>
A	O
selection	O
of	O
enemies	O
from	O
Half-Life	B-Application
populate	O
the	O
game	O
,	O
including	O
alien	O
creatures	O
such	O
as	O
headcrabs	O
and	O
Vortigaunts	O
.	O
</s>
<s>
Blue	O
Shift	O
does	O
not	O
elaborate	O
on	O
the	O
storyline	O
in	O
Opposing	B-Application
Force	I-Application
,	O
the	O
preceding	O
expansion	O
pack	O
,	O
and	O
no	O
enemy	O
characters	O
or	O
weapons	O
introduced	O
in	O
it	O
appear	O
in	O
the	O
game	O
.	O
</s>
<s>
Blue	O
Shift	O
is	O
set	O
in	O
the	O
same	O
location	O
and	O
time	O
frame	O
as	O
that	O
of	O
Half-Life	B-Application
,	O
taking	O
place	O
at	O
a	O
remote	O
New	O
Mexico	O
laboratory	O
called	O
the	O
Black	O
Mesa	O
Research	O
Facility	O
.	O
</s>
<s>
In	O
Half-Life	B-Application
,	O
the	O
player	O
takes	O
on	O
the	O
role	O
of	O
Gordon	O
Freeman	O
,	O
a	O
scientist	O
involved	O
in	O
an	O
accident	O
that	O
opens	O
an	O
interdimensional	O
portal	O
to	O
the	O
borderworld	O
of	O
Xen	O
,	O
allowing	O
the	O
alien	O
creatures	O
of	O
Xen	O
to	O
attack	O
the	O
facility	O
.	O
</s>
<s>
As	O
in	O
Opposing	B-Application
Force	I-Application
,	O
Blue	O
Shift	O
shows	O
the	O
events	O
of	O
Half-Life	B-Application
from	O
the	O
perspective	O
of	O
a	O
different	O
protagonist	O
.	O
</s>
<s>
Blue	O
Shift	O
begins	O
similarly	O
to	O
Half-Life	B-Application
,	O
as	O
Barney	O
Calhoun	O
rides	O
a	O
train	O
through	O
the	O
Black	O
Mesa	O
research	O
facility	O
to	O
reach	O
his	O
place	O
of	O
work	O
.	O
</s>
<s>
At	O
one	O
location	O
,	O
he	O
witnesses	O
Freeman	O
's	O
capture	O
by	O
Marines	O
midway	O
through	O
Half-Life	B-Application
,	O
before	O
eventually	O
stabilizing	O
at	O
the	O
intended	O
teleport	O
location	O
with	O
Rosenberg	O
at	O
the	O
outskirts	O
of	O
Black	O
Mesa	O
,	O
where	O
they	O
then	O
escape	O
the	O
facility	O
in	O
a	O
company	O
SUV	O
.	O
</s>
<s>
Blue	O
Shift	O
was	O
announced	O
in	O
the	O
second	O
quarter	O
of	O
2000	O
as	O
part	O
of	O
an	O
upcoming	O
Dreamcast	B-Operating_System
port	O
of	O
Half-Life	B-Application
.	O
</s>
<s>
While	O
the	O
port	O
was	O
developed	O
by	O
Captivation	O
Digital	O
Laboratories	O
,	O
Blue	O
Shift	O
was	O
developed	O
by	O
Gearbox	O
Software	O
,	O
who	O
also	O
developed	O
the	O
first	O
Half-Life	B-Application
expansion	O
,	O
Opposing	B-Application
Force	I-Application
.	O
</s>
<s>
The	O
game	O
had	O
the	O
working	O
title	O
Half-Life	B-Application
:	O
Guard	O
Duty	O
;	O
publisher	O
Sierra	O
Entertainment	O
announced	O
the	O
name	O
Blue	O
Shift	O
on	O
August	O
30	O
,	O
2000	O
.	O
</s>
<s>
As	O
with	O
Opposing	B-Application
Force	I-Application
,	O
the	O
title	O
has	O
a	O
double	O
meaning	O
,	O
referring	O
to	O
both	O
the	O
blue	O
shift	O
light	O
phenomenon	O
and	O
the	O
name	O
of	O
Barney	O
's	O
shift	O
.	O
</s>
<s>
The	B-Operating_System
Dreamcast	I-Operating_System
port	O
would	O
include	O
higher	O
detail	O
models	O
and	O
textures	O
that	O
were	O
double	O
the	O
polygon	B-General_Concept
count	I-General_Concept
of	O
Valve	O
's	O
original	O
Half-Life	B-Application
models	O
.	O
</s>
<s>
At	O
the	O
European	O
Computer	O
Trade	O
Show	O
in	O
September	O
2000	O
,	O
information	O
about	O
Blue	O
Shifts	O
story	O
and	O
development	O
direction	O
was	O
revealed	O
,	O
along	O
with	O
a	O
release	O
date	O
of	O
November	O
1	O
,	O
2000	O
,	O
for	O
the	B-Operating_System
Dreamcast	I-Operating_System
version	O
of	O
Half-Life	B-Application
.	O
</s>
<s>
On	O
March	O
29	O
,	O
2001	O
,	O
Sierra	O
announced	O
that	O
Blue	O
Shift	O
would	O
also	O
be	O
released	O
for	O
Windows	B-Application
as	O
a	O
standalone	O
game	O
that	O
would	O
not	O
require	O
the	O
original	O
Half-Life	B-Application
to	O
run	O
.	O
</s>
<s>
The	O
new	O
models	O
developed	O
for	O
the	B-Operating_System
Dreamcast	I-Operating_System
version	O
would	O
also	O
be	O
included	O
in	O
the	O
PC	O
version	O
as	O
the	O
Half-Life	B-Application
High	O
Definition	O
pack	O
,	O
and	O
could	O
be	O
applied	O
to	O
Half-Life	B-Application
and	O
Opposing	B-Application
Force	I-Application
.	O
</s>
<s>
On	O
June	O
16	O
,	O
2001	O
,	O
Sierra	O
canceled	O
the	B-Operating_System
Dreamcast	I-Operating_System
port	O
of	O
Half-Life	B-Application
,	O
citing	O
"	O
changing	O
market	O
conditions	O
"	O
.	O
</s>
<s>
A	O
late	O
build	O
of	O
the	B-Operating_System
Dreamcast	I-Operating_System
version	O
eventually	O
leaked	O
online	O
,	O
featuring	O
complete	O
versions	O
of	O
Half-Life	B-Application
and	O
Blue	O
Shift	O
.	O
</s>
<s>
Blue	O
Shift	O
and	O
the	O
High	O
Definition	O
pack	O
were	O
initially	O
absent	O
from	O
the	O
launch	O
of	O
Valve	O
's	O
content	O
delivery	O
system	O
Steam	B-Application
in	O
September	O
2003	O
,	O
despite	O
the	O
presence	O
of	O
both	O
Half-Life	B-Application
and	O
Opposing	B-Application
Force	I-Application
on	O
the	O
system	O
.	O
</s>
<s>
The	O
game	O
was	O
released	O
on	O
Steam	B-Application
on	O
August	O
29	O
,	O
2005	O
along	O
with	O
the	O
High	O
Definition	O
Pack	O
.	O
</s>
<s>
Blue	O
Shift	O
was	O
also	O
published	O
as	O
part	O
of	O
Sierra	O
's	O
Half-Life	B-Application
:	O
Generation	O
compilation	O
in	O
2002	O
,	O
</s>
<s>
The	O
game	O
has	O
sold	O
around	O
800,000	O
copies	O
at	O
retail	O
,	O
excluding	O
digital	O
sales	O
on	O
Steam	B-Application
.	O
</s>
<s>
In	O
a	O
review	O
for	O
IGN	O
,	O
critic	O
Tal	O
Blevins	O
noted	O
that	O
Blue	O
Shifts	O
gameplay	O
"	O
is	O
pretty	O
much	O
what	O
we	O
've	O
come	O
to	O
expect	O
out	O
of	O
Half-Life	B-Application
"	O
by	O
blending	O
action	O
and	O
puzzle	O
solving	O
,	O
stating	O
that	O
the	O
latter	O
"	O
were	O
all	O
logical	O
and	O
well	O
done	O
,	O
although	O
some	O
of	O
the	O
jumping	O
puzzles	O
were	O
frustrating	O
"	O
.	O
</s>
<s>
In	O
addition	O
,	O
Kasavin	O
described	O
the	O
graphical	O
enhancements	O
brought	O
about	O
by	O
the	O
High	O
Definition	O
pack	O
as	O
"	O
helpful	O
"	O
,	O
but	O
noted	O
that	O
"	O
they	O
still	O
do	O
n't	O
make	O
Half-Life	B-Application
look	O
like	O
a	O
new	O
game	O
—	O
nor	O
are	O
many	O
of	O
the	O
changes	O
themselves	O
very	O
noticeable	O
"	O
.	O
</s>
<s>
Although	O
writing	O
that	O
the	O
game	O
"	O
feels	O
like	O
just	O
a	O
few	O
more	O
levels	O
for	O
the	O
original	O
game	O
"	O
,	O
he	O
noted	O
that	O
this	O
is	O
what	O
Blue	O
Shift	O
was	O
designed	O
to	O
be	O
,	O
given	O
its	O
origins	O
as	O
an	O
add-on	O
for	O
a	O
Dreamcast	B-Operating_System
version	O
of	O
Half-Life	B-Application
.	O
</s>
<s>
Eurogamer	O
echoed	O
criticism	O
on	O
the	O
game	O
's	O
length	O
;	O
reviewer	O
Tom	O
Bradwell	O
commented	O
that	O
"	O
although	O
I	O
'm	O
hard	O
pressed	O
to	O
criticize	O
what	O
you	O
get	O
,	O
the	O
complete	O
absence	O
of	O
everything	O
we	O
've	O
learnt	O
from	O
the	O
likes	O
of	O
Counter-Strike	B-Application
and	O
everything	O
since	O
is	O
frankly	O
bizarre	O
"	O
.	O
</s>
<s>
PC	O
Zones	O
review	O
closed	O
by	O
commenting	O
that	O
"	O
as	O
a	O
Dreamcast	B-Operating_System
extra	O
it	O
works	O
perfectly	O
,	O
but	O
as	O
a	O
standalone	O
PC	O
title	O
there	O
's	O
not	O
nearly	O
enough	O
to	O
it.	O
"	O
</s>
<s>
Jim	O
Preston	O
reviewed	O
the	O
PC	O
version	O
for	O
Next	O
Generation	O
,	O
and	O
recommended	O
players	O
play	O
the	O
Half-Life	B-Application
mods	O
They	O
Hunger	O
or	O
Day	B-Application
of	I-Application
Defeat	I-Application
instead	O
.	O
</s>
