Love me some 2D sprites in a 3D environment, it always makes me happy.
This is cool! I'd actually love an adventure game in this style with mob enemies and more dungeon to explore!
I accidentally managed to boundary break the wyrm stage and was quite impressed the boss followed me out of the bounds of the level and then back in again without stopping the fight. One slight issue I had with the controls is that the dodge roll always seemed to go to the right, which made things a little tricky when I was moving to the left and trying to avoid attacks. I also got down to zero health without dying in a couple fights, but didn't happen for the spider or the final boss.
I enjoyed the limb swapping mechanic; really appreciated the shot on your character before the final fight so you get to look at what you've become, made me wonder what other creations are possible :)
Really cool stuff, well done!