<s>
System	B-Operating_System
's	I-Operating_System
Twilight	I-Operating_System
:	O
An	O
Abstract	O
Fairy	O
Tale	O
is	O
a	O
graphical	O
interactive	O
fiction	O
computer	O
game	O
created	O
by	O
Andrew	O
Plotkin	O
and	O
released	O
in	O
1994	O
.	O
</s>
<s>
The	O
puzzles	O
include	O
variations	O
of	O
Set	O
,	O
Black	O
Box	O
,	O
and	O
Sokoban	B-Device
,	O
as	O
well	O
as	O
many	O
others	O
.	O
</s>
<s>
The	O
overarching	O
story	O
is	O
an	O
allegory	B-Algorithm
in	O
which	O
the	O
player	O
and	O
other	O
characters	O
are	O
programs	O
in	O
a	O
broken	O
,	O
dysfunctional	O
computer	O
environment	O
.	O
</s>
<s>
Originally	O
,	O
Plotkin	O
released	O
System	B-Operating_System
's	I-Operating_System
Twilight	I-Operating_System
as	O
shareware	B-License
.	O
</s>
<s>
Since	O
2000	O
,	O
it	O
has	O
been	O
re-released	O
as	O
binary-only	O
freeware	B-License
.	O
</s>
<s>
It	O
runs	O
only	O
on	O
the	O
Mac	B-Application
OS	I-Application
Classic	I-Application
environment	O
,	O
but	O
can	O
be	O
run	O
in	O
emulation	B-Application
on	O
other	O
platforms	O
.	O
</s>
<s>
MacAddict	O
commented	O
that	O
System	B-Operating_System
's	I-Operating_System
Twilight	I-Operating_System
felt	O
similar	O
to	O
3	B-Operating_System
in	I-Operating_System
Three	I-Operating_System
,	O
with	O
hard	O
puzzles	O
,	O
quality	O
sound	O
and	O
graphics	O
,	O
and	O
a	O
witty	O
storyline	O
.	O
</s>
<s>
Inside	B-Application
Mac	I-Application
Games	I-Application
rated	O
the	O
game	O
four	O
out	O
of	O
five	O
,	O
and	O
also	O
noted	O
the	O
game	O
's	O
similarity	O
to	O
3	B-Operating_System
in	I-Operating_System
Three	I-Operating_System
,	O
saying	O
it	O
took	O
"	O
the	O
genre	O
of	O
Cliff	O
Johnson	O
game	O
 [ ... ] 	O
to	O
new	O
heights.	O
"	O
</s>
<s>
Inside	B-Application
Mac	I-Application
Games	I-Application
called	O
the	O
game	O
"	O
very	O
well	O
crafted	O
in	O
all	O
aspects	O
"	O
:	O
the	O
story	O
is	O
involved	O
and	O
complex	O
and	O
the	O
puzzles	O
are	O
clever	O
and	O
original	O
.	O
</s>
<s>
Adventure	O
Gamers	O
felt	O
that	O
System	B-Operating_System
's	I-Operating_System
Twilight	I-Operating_System
improved	O
on	O
"	O
Cliff	O
Johnson	O
’s	O
metapuzzle	O
adventures	O
"	O
by	O
adding	O
"	O
some	O
much-needed	O
nonlinearity	O
as	O
well	O
as	O
a	O
stronger	O
narrative.	O
"	O
</s>
<s>
AllGame	O
rated	O
System	B-Operating_System
's	I-Operating_System
Twilight	I-Operating_System
three	O
and	O
a	O
half	O
out	O
of	O
five	O
stars	O
,	O
calling	O
it	O
"	O
a	O
very	O
unusual	O
game	O
"	O
with	O
an	O
ending	O
that	O
was	O
"	O
something	O
of	O
a	O
letdown	O
"	O
,	O
and	O
suggesting	O
that	O
it	O
would	O
appeal	O
to	O
people	O
who	O
like	O
hard	O
puzzles	O
.	O
</s>
