Rewards wise I think the base soul ash stuff is good, but I do think the rewards should be more progressive as you make your way through a layer as opposed to being a single payout at the end. Getting through 5 floors only to reach an unkillable boss after spending a not insignificant amount of time in there is a horrendous feeling. I'd rather you get some small amount of soul ash for every floor boss you kill on the way to the final one, even if its lop sided and the final one carries most of the rewards.
The reward structure in twisting corridors feels a mess to me. Why make 8 layers when only 4 have rewards? Why only 4 rewards some of which are super low effort like a title? I don't need power rewards coming from it but they could've put so much more in there.
And that's ignoring that frankly it doesn't feel great as a roguelike / lite. I've sunk so many hours into risk of rain 2 for instance for no rewards or nothing of permanence. Just purely for the fun of it, but torghast really doesn't capture that feeling. It just misses the mark on what makes those games fun imo.