One thing i noticed on itch.io recently when i decided to check what modern (if indie) stuff can still run on my ~2004 era retro PC is that pretty much 90% of games that also provide demos are adult/nsfw games.
(btw about half of the demos i tried worked fine while pretty much nothing made with Unity worked)
My experience is that most of the demos are for early access/kickstarter/vaporware stuff (and stuff that once was in that phase), or game jam versions that evolved into proper projects and list the jam version as a demo, but we may have browsed for different things. Though the adult stuff likely counts as early access since those games start with public proofs of concept to attract sugar daddies to their patreons to fund further development.
Old Unity versions stuff should be at least somewhat playable on ancient hardware/32bit OSes (maybe after tinkering with the quality settings and launch commands), but all the newer/more featured games tend to use newer versions that are leakier and with various compatibility-breaking bugs. And you can't search by engine version to dig out the few games that stick to old Unity, so yeah. BTW one weird Unity behavior I noticed recently, if I try to run a game using it from a USB-connected external drive then instead of taking that much longer to launch, it will immediately crash with a misleading error about running out of memory (but will launch from the main drive).
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Not an RPG but an obscure thing nonetheless: Aliens: Attack on Colony, an Alien Breed-like shooter from the early 00s The Games Factory/Multimedia Fusion/Game Maker boom in potato. Alien fangames were a popular choice, and this is the most polished one. While it was never finished (supposedly it ended in late beta stage and the next release was to be the full game), the beginning of the campaign and the skirmish mode are available and the latter is quite fun, with destructible environment and lots of weapons to blow things up with.
Download:
https://www.mediafire.com/file/9v668dxfuj4ntpe/AliensAOCv2_1.zip/file
Game's old website:
https://web.archive.org/web/20040102082427/http://www.baltix.home.pl/AliensAOC/ (the second missing image for site's language choice leads to the English version)
The guy behind it tried to reboot and overhaul the project some years later as a coop multiplayer shooter, with title change to Alien Territory (
dev thread,
preview video and
another one,
planned features list), and reportedly there was a server for it running for some time, but that was after my interests drifted elsewhere and so I don't know how good or bad it was (you can find the client for the "old"/earlier version of it together with some dev screenshots
here, ~26 MB to download, but it's useless as there's no single player mode and no option to host yourself).
Also:
https://almoradarkosen.com/features/ - seems like this is his current thing he dropped the above games for (some mobile hack&slash, which I guess fits this thread a bit more)
