<s>
Playing	B-Application
History	I-Application
2	I-Application
-	I-Application
Slave	I-Application
Trade	I-Application
is	O
an	O
educational	O
game	O
developed	O
and	O
published	O
by	O
Serious	B-Application
Games	I-Application
Interactive	I-Application
,	O
and	O
released	O
on	O
September	O
13	O
,	O
2013	O
,	O
for	O
Windows	B-Application
and	O
Mac	B-Device
OS	I-Device
X	I-Device
on	O
the	O
Steam	B-Application
platform	O
.	O
</s>
<s>
The	O
game	O
caused	O
a	O
great	O
deal	O
of	O
controversy	O
for	O
its	O
inclusion	O
of	O
a	O
"	O
Slave	B-Application
Tetris	I-Application
"	O
minigame	O
,	O
which	O
was	O
later	O
removed	O
,	O
and	O
other	O
depictions	O
of	O
slavery	O
seen	O
to	O
be	O
offensive	O
.	O
</s>
<s>
Other	O
minigames	O
in	O
the	O
game	O
formerly	O
included	O
a	O
Tetris-like	O
mode	O
in	O
which	O
the	O
player	O
needed	O
to	O
"	O
stack	O
"	O
slaves	O
in	O
the	O
storage	O
compartment	O
of	O
the	O
ship	O
.	O
</s>
<s>
During	O
the	O
game	O
's	O
campaign	O
on	O
Steam	B-Application
Greenlight	O
,	O
users	O
raised	O
concerns	O
about	O
the	O
game	O
but	O
the	O
game	O
's	O
developers	O
defended	O
the	O
controversial	O
"	O
Slave	B-Application
Tetris	I-Application
"	O
mode	O
.	O
</s>
<s>
After	O
the	O
game	O
was	O
released	O
on	O
Steam	B-Application
,	O
several	O
years	O
after	O
its	O
original	O
release	O
date	O
,	O
a	O
large	O
number	O
of	O
users	O
complained	O
that	O
the	O
game	O
trivialized	O
slavery	O
.	O
</s>
<s>
The	O
game	O
's	O
developers	O
removed	O
the	O
Tetris-like	O
level	O
and	O
issued	O
an	O
apology	O
on	O
Steam	B-Application
.	O
</s>
