A big recommendation I can dish out to everybody who seeks for some raw underground gaming experience are the works of Hodslate.

I had 2 of his games on my blog already; he is a australian roofworker iirc and is doing all of his games in his spare time, not using any premade assets or textures. His games are raw, dark, and oppressive. Quite like black metal gone video game.

He has quite some output. Didn't manage to play his more recent games till yet.

https://hodslate-productions.itch.io/