Kingdom Rush - Tower Defense series:   PC-Release GOG '1st Release (non PC)'
   * 1. Kingdom Rush . . . . . . . . . . . . . . . . 06.01.2014   4.4   19.12.2011
   * 2. Kingdom Rush Frontiers . . . . . . . . 25.07.2016   4.4   06.06.2013
   * 3. Kingdom Rush Origins  . . . . . . . . . 18.10.2018   4.5   20.11.2014
   o 4. Kingdom Rush Vengeance . . . . . . 15.10.2020  NYA  22.11.2018
   o 5. Legends of Kingdom Rush . . . . . . . -- . -- . ----  NOG  11.06.2021
   o x. Iron Marines  . . . . . . . . . . . . . . . . . 15.05.2019  NYA  14.09.2017
All games pure 64 bit, SiPl, no controller (but KBM), Ironhide Game Studio (Devs. & Publisher).
*: being on GOG with a GNU/Linux version, NOG: not on GOG, NYA: not yet available (for GNU/Linux).
   -> https://www.ironhidegames.com/Games
   -> https://en.wikipedia.org/wiki/Kingdom_Rush

As Game engine it seems to use Löve/Love2d with SDL2 till the 3rd sequel ('Origins'), the 4th ('Vengeance') is reported
to be cocos2d-x version 3.x, unfortunately, so a soon available GNU/Linux port is very unlikely (see 3rd posting below
about conversation with support).
I own the first three ("*") and played with all three:
All don't have visible bugs, have FullHD graphics, are addictive and fun, showing internal versions:
kr1-desktop-4.2.33, kr2-desktop-4.2.33, and kr3-desktop-4.2.15 (state on 01. July 2021),
with update on 16.12.2021 bringing kr1-desktop-5.6.12.
Really lovely graphics, well documented in game - just fantastic.
I would give all three games 5 stars from my 1st impression - and this is well deserved.

As a side note there is a progression in those releases: with version 2, a skill system is
also introduced for the hero (next to that of the towers being present in the 1st part),
and the 3rd part now have a second direct controlled attack (1st game it was meteor shower,
here it is lightning and arrow rain). But the very good playing mechanics is kept.

I have found one annoyance which I would call bug (but really inferior):
Using 4k (3840 × 2160 pix) resolution with an 31.5" screen, the mouse cursor looks nice, but in severe battle
it is too small and with low contrast - so I would appreciate an option to enlarge it and make it visible using
high contrast (i.e. visible color) - maybe putting this in 2 options would please all.

So I will mail to the Devs reporting the bug and asking for the three versions missing a GNU/Linux version
on GOG and if these will come in near future (maybe even having a planned date for it).

I bought also "Iron Marines" which I would love to play - but I have overlooked that it is not available
for Linux on GOG (while Steam seems to have a Linux version) and am happy that GOG granted
a refund despite giving correct info on the product page (while stating 32 bit libs necessary for the 1st part -
while all 3 are pure 64 bit games [same situation for Bridge constructor series for parts 1-3;
both series do have great quality of life!].
Maybe GOG will improve on giving right info someday; my info seems to be of no interest for support) ...

The other two games missing totally are being part of the Kingdom Rush saga and are quite young -
and thus may emerge on GOG in future.

I will add any info from the Devs to this forum post ...
-> Changed post and added post 3 with the conversation to share with GOG gamers.

Oh, that means I can check the first game, huh. Nice.

Conversation with Support of Kingdom Rush series

~~
JMB: # 18.12.2021 20:07 CET
I was happy to see that your new game "Kingdom Rush IV - Vengeance"
is now available on GOG:
* https://www.gog.com/news/release_kingdom_rush_vengeance
but unfortunately no longer for GNU/Linux (and not for macOS, but
the latter may be problematic in the current situation).
Will the GNU/Linux port follow soon - or are there technical problems
with the porting?
As your games work flawlessly on GNU/Linux, I was really astonished that
a Linux port is not present on day one - and not amused that GOG had no
word that your series being available in 3 platforms are now only
available for Windows.
I am not the only one who would have bought your new game directly -
but I need a GNU/Linux port.
Is this a new trend as Iron Marines was available on two platforms -
but not on GNU/Linux.
In the former mail I asked about the used game engine ... it may be
'Löve/Love2d with SDL2' - but would be happy to update my overview
on your games on GOG forum:
* https://www.gog.com/forum/kingdom_rush_series/kingdom_rush_saga_technical_overview_gnulinux_centric
with some information form you.
So anything you can explain I will happily share with other gamers
on GOG forum.
And your games are really great and deserve a native port for GNU/Linux.
#
IRONHIDE GAME STUDIO: # 20.12.2021 17:40 CET
Unfortunately there are no plans (as of yet) to port KRV and IM to GNU/Linux.
Also yes, you're correct that our game engine is Love2d.
Thank you for your support.
#
JMB: # 20.12.2021 17:56 CET
Could you give some inside why the GNU/Linux porting was stopped - Love2D is
written in C++, so it should be portable a typically just a different compile
target - or is this picture much to simplistic to give reality?
And from my point of view the older games were ported well, so I am just
curious why there is no longer support for GNU/Linux.
Would be happy to share you answer with other gamers on GOG forum.
#
IRONHIDE GAME STUDIO: # 22.12.2021 21:10 CET
So I was talking with cigumo, one of our lead programmers, and he shared with
me that KRV is not made with love2d, but with cocos2d-x version 3.x which
isn't easily ported to linux. As a small teams with lots of projects it just
isn't something that we can do at the moment, but still we appreciate
the feedback and will definitly consider it in the future.
~~
See Kingdom Rush Vengeance announcement comments.