Happier ending: I did manage to finally get past it as the RNG took pity on me near the end (putting on my wrist support also didn't hurt), total time on it took almost exactly one hour.
The game seemed to be in a rather finished state so I think it is more than reasonable to leave it as-is, I just felt I should point it out as I thought the body of the game was a legit hidden gem. The pacing of giving new forms, the secrets, the various puzzles built around the main mechanic were all rather well realized, some of it is a bit rough around the edges but I'd unreservedly call it a true pleasant surprise of a game. It's what made ending on what felt like to me at least an unforced error (FWIW I think the concept of the final confrontation is pretty good) a bit of a downer. Or to put it another way, if I thought that most of the game wasn't pretty good I wouldn't care enough to bother pointing out the bits that felt like they needed a bit more fine tuning.
Anyways thanks for taking the time to read and reply, and I'll likely take a glance at your most recent game in the near future as this game showed that you are capable of putting together something rather creative.