DrakoGhoul ,
Rutonat
Maybe I didn't choose the most appropriate word.
Steal, Copy, Absorption, Mimicking...
The term is not as important as the effect itself.
"You had something, but after examining your essence in detail, I can have it too."
You'll get
Bad Ending if you try to absorb Kenny's head and don't purge it first.
Personally, I see Corruption as something like a loss of control. You will be stronger, but you will gradually lose yourself as you will be more and more a monster that is governed only by basic instincts.
In the dialogues around Bailey, there was a mention where MC said he thought he had limited control over black slime, precisely because he absorbed Kenny's head and part of his abilities. But I haven't seen a version of the dialogues where you haven't absorbed his head.
I also can't answer how far his ability to steal (or what he actually does) abilities goes.
There are different types of monsters, so it is possible that his abilities are limited to those powers that come from the same evolutionary tree. But it is possible that MC is (or will be) so malleable that if he understands enough how powers works, he can adapt his body to use it. So far, we don't have enough information to be sure.
P.S.
Have you seen TV show
Heroes?
There was a villain named Sylar who could adapt his body to use ALL superpowers.
But first he had to open the person's head and examine brain to understand exactly how power worked.
It didn't matter what power it was. If he knew how it worked, he could adjust his body so he could use it.
It reminds me a bit of MC's abilities.