It must feel great to devote yourself to a passion project and it turns out to actually work and people use it.
I assume this is a passion project because I can't imagine getting funds for a project like this, specially when it might conflict with upstream licenses.
There’s a few games out there that have absolutely immense fandoms in places unexpected - Heroes III is absolutely HUGE in countries east of the old iron curtain, partially probably because it runs well on older computers but also because it’s one of the best games ever made.
As someone from that region I know the reason: it's the hot seat feature[0].
You only needed one copy of the game and one PC for you and your friends to play together. Every class in school had at least one guy who had his own PC, who often invited friends over to play after class and since commie blocks are particularly walkable, we could all return home on our own.
I spent a good chunk of my preteen years like that.
[0] really badly translated to what directly translates back to "flaming buttcheeks".
Late 90s largely - we started with H2 and when H3 came out, enthusiastically switched to it as soon as the two guys who would always have friends over got their copies. They always had the latest stuff because they were upper-middle class and back then even such people would live in commie blocks, since it was free real estate, and send their kids to public schools.
H4 didn't make such a splash because even though it was better balanced, it felt like a downgrade in many respects.
I went to a different middle school so when I regained contact with my grade school friends they were already either exploring alcohol and sex or got sucked into WoW - in one case even both.
Anyway H3 left a mark on my generation thanks to its great replayability and social aspect that fit well into post-communist reality, with walkable, but hideous architecture and absent parents, majority of whom were working overtime(by western standards at least).
Heroes is significant in the eastern block because, in my opinion, Heroes 1 and 2, effectively came close to becoming 3D chess with level-ups. Then, you add a charming crayola palette (no black and white) , almost perfect balancing, and an award-winning opera/orchestra soundtrack - you have yourself a timeless jewel.
VCMI dont conflict with licenses because it's not reverse engineering effort, but engine created from scratch and licensed under GPL. Pretty much like OpenMW, OpenRA and other purely open source projects.
Of course to play it you need to buy proprietary assets.
There is a big problem with creating actually free assets:
* If everything will look completely different from original game majority of fans not gonna like it even if quality gonna be really high. As you can guess fans of old games are really opinionated and hard to pleasure.
* If they looks too similar to original game then Ubisoft can righfully claim copyright infrigement so it will be impossible to distribute assets in Debian, Google Play and other stores.
Actually same problem is valid for any open source game reimplementations except simulators where you can claim that you copying some original and not someone else commercial game.
It's very much possible to just take VCMI and HoMM3 mechanics and create completely different game on top of it. Engine was intentionally designed for modding after all, but again it's unlikely that many fans will play it.
I assume this is a passion project because I can't imagine getting funds for a project like this, specially when it might conflict with upstream licenses.
In any case congratulations to the developers.