Thanks a lot for playing and your always comprehensive analysis.
As always with my poor time management I was working on this til the last hour of the jam so I never get enough testing done and i just rush to get something playable out, thanks for pointing out a bunch of the bugs and playing through a few times.
As you guessed the mutation is random and just gives you a mutation of the animal regardless of what part you click on(You click on any bear part including the arm the human has and it will take from a pool of bear parts and give you one randomly. It gives you nothing if you happen to already have the part.) The pool of mutations is pretty low for each of the animals so you'll normally get the same thing, except for the human who has a full set.
If I had more time I would have expanded on the mutation system a lot more and a bunch more enemy types and mixing other enemies together for variation.
Shame to see you didn't have an entry this jam, always looking forward to what you put out.