<s>
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
,	O
also	O
known	O
as	O
HOI4	B-Application
,	O
is	O
a	O
grand	O
strategy	O
computer	B-Application
wargame	I-Application
developed	O
by	O
Paradox	O
Development	O
Studio	O
and	O
published	O
by	O
Paradox	O
Interactive	O
.	O
</s>
<s>
It	O
is	O
the	O
sequel	O
to	O
2009	O
's	O
Hearts	B-Application
of	I-Application
Iron	I-Application
III	I-Application
and	O
the	O
fourth	O
main	O
installment	O
in	O
the	O
Hearts	B-Application
of	I-Application
Iron	I-Application
series	O
.	O
</s>
<s>
Like	O
previous	O
games	O
in	O
the	O
series	O
,	O
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
is	O
a	O
grand	O
strategy	O
wargame	B-Application
that	O
focuses	O
on	O
World	O
War	O
II	O
.	O
</s>
<s>
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
is	O
a	O
grand	O
strategy	O
wargame	B-Application
that	O
primarily	O
revolves	O
around	O
World	O
War	O
II	O
.	O
</s>
<s>
For	O
the	O
ground	O
forces	O
,	O
the	O
player	O
may	O
train	O
,	O
customize	O
,	O
and	O
command	O
divisions	O
consisting	O
of	O
various	O
types	O
of	O
infantry	B-Protocol
,	O
tanks	O
,	O
and	O
other	O
units	O
.	O
</s>
<s>
The	O
navy	O
and	O
air	O
force	O
also	O
require	O
men	O
and	O
equipment	O
,	O
including	O
the	O
actual	O
warships	B-Application
and	O
warplanes	O
that	O
are	O
used	O
in	O
combat	O
.	O
</s>
<s>
Land	O
in	O
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
is	O
divided	O
into	O
tiny	O
regions	O
known	O
as	O
provinces	O
(	O
also	O
called	O
tiles	O
)	O
,	O
which	O
are	O
grouped	O
to	O
form	O
states	O
.	O
</s>
<s>
The	O
major	O
seas	O
and	O
oceans	O
(	O
for	O
warships	B-Application
)	O
and	O
the	O
sky	O
(	O
for	O
warplanes	O
)	O
are	O
similarly	O
divided	O
into	O
different	O
regions	O
.	O
</s>
<s>
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
also	O
attempts	O
to	O
recreate	O
the	O
complex	O
diplomatic	O
relationships	O
of	O
the	O
day	O
.	O
</s>
<s>
Otherwise	O
,	O
ideologies	O
may	O
come	O
to	O
power	O
violently	O
through	O
coups	O
,	O
civil	B-Application
wars	I-Application
,	O
or	O
forced	O
subjugation	O
by	O
a	O
foreign	O
power	O
.	O
</s>
<s>
While	O
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
does	O
feature	O
some	O
scripted	O
events	O
,	O
the	O
game	O
features	O
a	O
"	O
national	O
focus	O
"	O
system	O
that	O
makes	O
fixed	O
events	O
less	O
necessary	O
than	O
in	O
previous	O
installments	O
in	O
the	O
series	O
.	O
</s>
<s>
Subsequent	O
updates	O
and	O
DLCs	B-Protocol
have	O
added	O
focus	O
trees	O
to	O
other	O
nations	O
as	O
well	O
.	O
</s>
<s>
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
also	O
introduces	O
the	O
concept	O
of	O
"	O
world	O
tension	O
"	O
,	O
an	O
abstract	O
representation	O
of	O
how	O
close	O
the	O
world	O
is	O
to	O
global	O
war	O
,	O
on	O
a	O
scale	O
from	O
0	O
to	O
100	O
.	O
</s>
<s>
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
was	O
announced	O
in	O
2014	O
and	O
was	O
originally	O
slated	O
for	O
a	O
late	O
2015	O
release	O
.	O
</s>
<s>
In	O
March	O
2016	O
,	O
it	O
was	O
announced	O
that	O
the	O
game	O
,	O
built	O
with	O
the	O
Clausewitz	B-Application
Engine	I-Application
,	O
would	O
be	O
released	O
on	O
6	O
June	O
2016	O
,	O
which	O
was	O
the	O
72nd	O
anniversary	O
of	O
the	O
Normandy	O
landings	O
.	O
</s>
<s>
The	O
expansion	O
also	O
includes	O
a	O
revamped	O
focus	O
tree	O
for	O
France	O
(	O
both	O
Free	O
and	O
Vichy	O
)	O
,	O
a	O
new	O
one	O
for	O
Portugal	O
,	O
and	O
two	O
focus	O
trees	O
for	O
the	O
different	O
sides	O
of	O
the	O
Spanish	O
Civil	B-Application
War	I-Application
,	O
one	O
for	O
the	O
Nationalists	O
and	O
one	O
for	O
the	O
Republicans	O
.	O
</s>
<s>
It	O
also	O
includes	O
a	O
reworked	O
national	O
focus	O
tree	O
for	O
Italy	O
,	O
as	O
well	O
as	O
new	O
national	O
focus	O
trees	O
for	O
both	O
Switzerland	B-Protocol
and	O
Ethiopia	O
.	O
</s>
<s>
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
was	O
developed	O
to	O
be	O
more	O
open-ended	O
than	O
previous	O
games	O
in	O
the	O
series	O
.	O
</s>
<s>
According	O
to	O
game	O
director	O
Dan	O
Lind	O
,	O
64%	O
of	O
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
players	O
use	O
mods	O
.	O
</s>
<s>
Kaiserreich	O
:	O
Legacy	O
of	O
the	O
Weltkrieg	O
,	O
a	O
mod	O
set	O
in	O
a	O
world	O
where	O
the	O
Central	O
Powers	O
won	O
World	O
War	O
I	O
.	O
Kaiserreich	O
is	O
considered	O
the	O
largest	O
and	O
most	O
in-depth	O
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
mod	O
by	O
many	O
community	O
members	O
.	O
</s>
<s>
Old	O
World	O
Blues	O
is	O
a	O
mod	O
set	O
in	O
the	O
Fallout	B-Application
universe	O
.	O
</s>
<s>
This	O
mod	O
has	O
been	O
praised	O
for	O
its	O
effective	O
portrayal	O
of	O
the	O
Fallout	B-Application
series	I-Application
within	O
a	O
grand	O
strategy	O
setting	O
.	O
</s>
<s>
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
was	O
a	O
commercial	O
success	O
.	O
</s>
<s>
It	O
sold	O
more	O
than	O
200,000	O
units	O
within	O
two	O
weeks	O
of	O
its	O
launch	O
,	O
which	O
made	O
it	O
the	O
fastest-selling	O
historically-themed	O
Paradox	O
title	O
by	O
that	O
time	O
,	O
ahead	O
of	O
Crusader	B-Application
Kings	I-Application
II	I-Application
and	O
Europa	B-Application
Universalis	I-Application
IV	I-Application
.	O
</s>
<s>
It	O
was	O
the	O
first	O
Hearts	B-Application
of	I-Application
Iron	I-Application
game	O
to	O
reach	O
the	O
million	O
mark	O
,	O
and	O
the	O
third	O
Paradox	O
title	O
after	O
,	O
Crusader	B-Application
Kings	I-Application
II	I-Application
and	O
Europa	B-Application
Universalis	I-Application
IV	I-Application
to	O
do	O
so	O
.	O
</s>
<s>
GameSpot	O
gave	O
the	O
game	O
a	O
positive	O
review	O
,	O
writing	O
that	O
"	O
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
embodies	O
the	O
hard	O
truths	O
about	O
all-consuming	O
war	O
and	O
the	O
international	O
politics	O
that	O
guide	O
it.	O
"	O
</s>
<s>
It	O
argued	O
that	O
the	O
tutorial	O
was	O
the	O
only	O
weak	O
point	O
,	O
and	O
that	O
"	O
for	O
the	O
dedicated	O
,	O
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
could	O
end	O
up	O
being	O
the	O
best	O
grand	O
strategy	O
game	O
in	O
some	O
time.	O
"	O
</s>
<s>
The	O
review	O
praised	O
the	O
layout	O
,	O
writing	O
"	O
thanks	O
to	O
an	O
unusually	O
striking	O
look	O
and	O
clean	O
,	O
easily	O
navigable	O
interface	O
,	O
the	O
biggest	O
challenges	O
Hearts	B-Application
of	I-Application
Iron	I-Application
4	I-Application
presents	O
us	O
with	O
are	O
the	O
good	O
kind	O
:	O
strategic	O
planning	O
,	O
division	O
composition	O
,	O
and	O
fine-tuning	O
economic	O
and	O
political	O
policies	O
"	O
.	O
</s>
<s>
IGN	O
went	O
on	O
to	O
conclude	O
that	O
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
"	O
is	O
a	O
strong	O
contender	O
for	O
the	O
title	O
of	O
the	O
ultimate	O
armchair-general	O
game	O
.	O
</s>
<s>
A	O
review	O
in	O
PC	O
Gamer	O
described	O
it	O
as	O
a	O
"	O
unique	O
,	O
beautiful	O
,	O
thrilling	O
wargame	B-Application
"	O
,	O
specifically	O
praising	O
its	O
frontline	O
system	O
and	O
production	O
mechanics	O
,	O
but	O
also	O
criticising	O
the	O
ideology	O
system	O
for	O
being	O
too	O
bland	O
,	O
and	O
finding	O
that	O
combat	O
was	O
somewhat	O
unintuitive	O
,	O
writing	O
"	O
while	O
I	O
found	O
several	O
flaws	O
when	O
I	O
stood	O
close	O
to	O
the	O
tapestry	O
,	O
it	O
's	O
important	O
to	O
remember	O
that	O
Hearts	B-Application
of	I-Application
Iron	I-Application
4	I-Application
exists	O
to	O
encompass	O
the	O
whole	O
sweep	O
of	O
the	O
war	O
"	O
.	O
</s>
<s>
Polygon	O
praised	O
the	O
openness	O
of	O
the	O
game	O
,	O
writing	O
that	O
"	O
Hearts	B-Application
of	I-Application
Iron	I-Application
4	I-Application
goes	O
a	O
step	O
further	O
,	O
allowing	O
players	O
to	O
take	O
control	O
of	O
nearly	O
every	O
single	O
nation-state	O
in	O
the	O
world	O
during	O
the	O
same	O
period	O
.	O
</s>
<s>
In	O
2022	O
,	O
six	O
years	O
after	O
the	O
game	O
's	O
release	O
and	O
shortly	O
after	O
the	O
By	O
Blood	O
Alone	O
expansion	O
,	O
Hearts	B-Application
of	I-Application
Iron	I-Application
IV	I-Application
hit	O
a	O
concurrent	O
player	O
record	O
of	O
about	O
70	O
,	O
000	O
,	O
owing	O
to	O
a	O
week-long	O
deal	O
that	O
temporarily	O
made	O
the	O
game	O
free-to-play	O
.	O
</s>
