<s>
OpenTTD	B-Application
is	O
a	O
business	B-Application
simulation	I-Application
game	I-Application
in	O
which	O
players	O
try	O
to	O
earn	O
money	O
by	O
transporting	O
passengers	O
,	O
minerals	O
and	O
goods	O
via	O
road	O
,	O
rail	O
,	O
water	O
and	O
air	O
.	O
</s>
<s>
It	O
is	O
an	O
open-source	B-Application
remake	O
and	O
expansion	O
of	O
the	O
1995	O
Chris	O
Sawyer	O
video	O
game	O
Transport	O
Tycoon	O
Deluxe	O
.	O
</s>
<s>
OpenTTD	B-Application
duplicates	O
most	O
features	O
of	O
Transport	O
Tycoon	O
Deluxe	O
and	O
has	O
many	O
additions	O
,	O
including	O
a	O
range	O
of	O
map	O
sizes	O
,	O
support	O
for	O
many	O
languages	O
,	O
custom	O
(	O
user-made	O
)	O
artificial	B-Application
intelligence	I-Application
(	O
AI	B-Application
)	O
,	O
downloadable	O
customisations	O
,	O
ports	O
for	O
several	O
widely	O
used	O
operating	B-General_Concept
systems	I-General_Concept
,	O
and	O
a	O
more	O
user-friendly	O
interface	O
.	O
</s>
<s>
OpenTTD	B-Application
also	O
supports	O
local	B-General_Concept
area	I-General_Concept
network	I-General_Concept
(	O
LAN	B-General_Concept
)	O
and	O
Internet	O
multiplayer	O
,	O
co-operative	O
and	O
competitive	O
,	O
for	O
up	O
to	O
255	O
players	O
.	O
</s>
<s>
OpenTTD	B-Application
is	O
free	B-License
and	I-License
open-source	I-License
software	I-License
licensed	O
under	O
the	O
GNU	B-License
GPL-2-0-only	I-License
and	O
is	O
under	O
ongoing	O
development	O
.	O
</s>
<s>
According	O
to	O
a	O
study	O
of	O
the	O
61,154	O
open-source	B-Application
projects	O
on	O
SourceForge	B-Application
in	O
the	O
period	O
between	O
1999	O
and	O
2005	O
,	O
OpenTTD	B-Application
ranked	O
8th	O
most	O
active	O
open-source	B-Application
project	O
to	O
receive	O
patches	O
and	O
contributions	O
.	O
</s>
<s>
Since	O
2018	O
,	O
the	O
project	O
uses	O
GitHub	B-Application
for	O
its	O
source	B-Architecture
repository	I-Architecture
and	O
bug	B-Application
tracker	I-Application
.	O
</s>
<s>
Starting	O
from	O
April	O
1	O
,	O
2021	O
,	O
the	O
game	O
is	O
now	O
also	O
available	O
on	O
Steam	B-Application
.	O
</s>
<s>
The	O
development	O
of	O
OpenTTD	B-Application
was	O
driven	O
by	O
the	O
desire	O
to	O
extend	O
the	O
abilities	O
of	O
Transport	O
Tycoon	O
Deluxe	O
to	O
support	O
user-made	O
additions	O
to	O
the	O
graphics	O
and	O
gameplay	O
,	O
as	O
well	O
as	O
the	O
desires	O
of	O
users	O
to	O
play	O
the	O
game	O
on	O
more	O
modern	O
operating	B-General_Concept
systems	I-General_Concept
and	O
alternative	O
computer	O
architectures	O
which	O
the	O
original	O
game	O
(	O
released	O
in	O
1994	O
for	O
DOS	B-Device
and	O
programmed	O
in	O
assembly	B-Language
language	I-Language
)	O
did	O
not	O
support	O
.	O
</s>
<s>
There	O
was	O
a	O
prior	O
attempt	O
to	O
modify	O
Transport	O
Tycoon	O
Deluxe	O
to	O
run	O
on	O
more	O
modern	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
OpenTTD	B-Application
was	O
preceded	O
by	O
a	O
commercial	O
conversion	O
of	O
Transport	O
Tycoon	O
Deluxe	O
to	O
run	O
on	O
Windows	B-Application
95	I-Application
.	O
</s>
<s>
It	O
was	O
created	O
in	O
1996	O
by	O
the	O
FISH	O
technology	O
group	O
,	O
but	O
Nola	O
released	O
in	O
1999	O
as	O
part	O
of	O
a	O
compilation	O
of	O
older	O
Tycoon	B-Application
games	I-Application
.	O
</s>
<s>
This	O
release	O
was	O
still	O
greatly	O
restricted	O
in	O
operating	B-General_Concept
systems	I-General_Concept
and	O
computer	O
architectures	O
it	O
could	O
run	O
on	O
.	O
</s>
<s>
Similarly	O
,	O
there	O
was	O
an	O
earlier	O
success	O
aiming	O
to	O
open	B-Application
Transport	I-Application
Tycoon	I-Application
Deluxe	I-Application
to	O
modification	O
by	O
users	O
.	O
</s>
<s>
TTDPatch	O
is	O
restricted	O
by	O
the	O
same	O
operating	B-General_Concept
system	I-General_Concept
and	O
computer	O
architecture	O
limits	O
as	O
Transport	O
Tycoon	O
Deluxe	O
and	O
has	O
limited	O
control	O
over	O
what	O
features	O
of	O
the	O
game	O
can	O
be	O
altered	O
.	O
</s>
<s>
In	O
2003	O
,	O
Ludvig	O
Strigeus	O
announced	O
that	O
he	O
intended	O
to	O
reverse	O
engineer	O
Transport	O
Tycoon	O
Deluxe	O
and	O
convert	O
the	O
game	O
to	O
C	B-Language
.	O
On	O
March	O
6	O
,	O
2004	O
this	O
re-engineered	O
Transport	O
Tycoon	O
Deluxe	O
was	O
released	O
and	O
named	O
OpenTTD	B-Application
.	O
</s>
<s>
,	O
OpenTTD	B-Application
is	O
still	O
under	O
active	O
development	O
.	O
</s>
<s>
The	O
early	O
development	O
of	O
OpenTTD	B-Application
focused	O
on	O
restructuring	O
the	O
code	O
to	O
improve	O
readability	O
and	O
extensibility	O
.	O
</s>
<s>
A	O
major	O
improvement	O
was	O
reprogramming	O
multiplayer	O
(	O
network	O
games	O
)	O
to	O
use	O
the	O
Internet	B-Protocol
Protocol	I-Protocol
,	O
allowing	O
multiplayer	O
gaming	O
online	O
and	O
over	O
modern	O
LANs	B-General_Concept
.	O
</s>
<s>
By	O
the	O
late	O
2000s	O
,	O
OpenTTD	B-Application
was	O
a	O
stable	O
and	O
popular	O
game	O
and	O
development	O
moved	O
toward	O
more	O
substantial	O
changes	O
.	O
</s>
<s>
2007	O
saw	O
the	O
development	O
of	O
support	O
for	O
custom	O
,	O
user-made	O
AIs	B-Application
,	O
which	O
can	O
provide	O
players	O
with	O
more	O
of	O
a	O
challenge	O
than	O
the	O
original	O
AI	B-Application
.	O
</s>
<s>
Other	O
more	O
major	O
changes	O
included	O
introducing	O
support	O
for	O
IPv6	B-Protocol
,	O
an	O
integrated	O
download	O
system	O
for	O
user-made	O
customisations	O
,	O
and	O
support	O
for	O
alternative	O
base	O
graphics	O
,	O
sound	O
and	O
music	O
sets	O
in	O
2009	O
.	O
</s>
<s>
Since	O
2007	O
,	O
OpenTTD	B-Application
is	O
gradually	O
being	O
rewritten	O
in	O
C++	B-Language
.	O
</s>
<s>
OpenTTD	B-Application
gameplay	O
is	O
very	O
similar	O
to	O
Transport	O
Tycoon	O
Deluxe	O
,	O
on	O
which	O
it	O
is	O
based	O
,	O
although	O
there	O
are	O
many	O
improvements	O
in	O
both	O
options	O
within	O
the	O
game	O
and	O
ease	O
of	O
use	O
.	O
</s>
<s>
For	O
rail	O
transport	O
,	O
new	O
track	O
technology	O
also	O
becomes	O
available	O
over	O
time	O
,	O
first	O
electrified	O
rail	O
,	O
then	O
monorail	B-Language
and	O
maglev	B-Language
track	O
.	O
</s>
<s>
OpenTTD	B-Application
can	O
be	O
played	O
by	O
one	O
player	O
,	O
against	O
a	O
computer	O
controlled	O
AI	B-Application
,	O
or	O
by	O
many	O
players	O
against	O
each	O
other	O
,	O
over	O
a	O
LAN	B-General_Concept
or	O
the	O
Internet	O
.	O
</s>
<s>
OpenTTD	B-Application
supports	O
multiplayer	O
games	O
for	O
up	O
to	O
255	O
players	O
between	O
15	O
different	O
transport	O
companies	O
,	O
and	O
can	O
be	O
played	O
both	O
over	O
a	O
LAN	B-General_Concept
or	O
over	O
the	O
Internet	O
.	O
</s>
<s>
Additional	O
changes	O
to	O
the	O
open	B-Application
source	I-Application
code	I-Application
which	O
modify	O
core	O
game	O
mechanics	O
(	O
"	O
patches	O
"	O
)	O
are	O
also	O
available	O
.	O
</s>
<s>
OpenTTD	B-Application
has	O
been	O
praised	O
for	O
the	O
number	O
of	O
improvements	O
it	O
has	O
made	O
to	O
the	O
original	O
Transport	O
Tycoon	O
Deluxe	O
,	O
such	O
as	O
the	O
AI	B-Application
,	O
graphics	O
,	O
sounds	O
,	O
and	O
ability	O
to	O
play	O
multiplayer	O
.	O
</s>
<s>
OpenTTD	B-Application
received	O
the	O
most	O
votes	O
for	O
Game	O
of	O
the	O
Year	O
for	O
the	O
2004	O
Amiga	O
Games	O
Award	O
.	O
</s>
<s>
Lewis	O
Denby	O
from	O
PC	O
Gamer	O
ranked	O
OpenTTD	B-Application
20th	O
in	O
its	O
May	O
2011	O
list	O
of	O
best	O
free	O
PC	O
games	O
.	O
</s>
<s>
Hungarian	O
Unix	O
Portal	O
users	O
chose	O
OpenTTD	B-Application
as	O
favourite	O
(	O
free	O
)	O
game	O
in	O
2005	O
,	O
2007	O
,	O
2009	O
,	O
and	O
2010	O
.	O
</s>
<s>
In	O
2014	O
OpenTTD	B-Application
was	O
named	O
by	O
PCGamer	O
among	O
the	O
"	O
Ten	O
top	O
fan	O
remade	O
classics	O
you	O
can	O
play	O
for	O
free	O
right	O
now	O
"	O
.	O
</s>
<s>
In	O
2015	O
and	O
2016	O
,	O
Rock	O
,	O
Paper	O
,	O
Shotgun	O
ranked	O
OpenTTD	B-Application
8th	O
on	O
its	O
The	O
50	O
Best	O
Free	O
Games	O
on	O
PC	O
list	O
.	O
</s>
