Thanks a lot for the feedback! I'm glad you liked it :)
For the flipped textures: if you mean the placeholder ones (various gates, vending/evolving/fusing machines) that's totally normal, if you men other that I maybe forgot please tell me more!
For the bosses I understand completely what you mean: in my recent playtests I had the same feeling so I'll definitely tweak some attack parameters and play with HP (it felt too long sometimes, not fun).