One of the major issues with the kraken in my opinion right now, is that he should NOT be able to conjur up another tentacle if he MISSES his attack. No other enemy in the game gets the side benefit of their move if their move misses (to my knowledge) and this would help to alleviate one of the biggest problems with the kraken: which is the fights can last forever

From a game mechanic standpoint the problem here is: The monster regenerates tentacles to take up time and then also stuns you to take up time, you can't do both of these or you just end up stun locked half the time and the game takes forever. Just give the Kraken himself some other stronger moves he can use if tentacles are out, keep the tentacles being fast. Maybe borrow the game mechanic of "immobilization" and one of your guys could get immobilized by the tentacles or something, but getting stun locked is terrible

I also concur with other posters that your mosters seem to be showing up too frequently, which is another reason why I disabled the mod. (I do think the normal monsters you designed, had some good work to them, just have them stop showing up so much)
I also agree that the art was awesome! But it does look kind of glitchy/weird when the kraken changes positions, I'm not sure if you can space it out differently when the Kraken changes positions

Also, like another poster pointed out, make sure that the monsters are coded correclty for their types.

Also, as a side note most monsters in the game have at least one main weakness to them, some of your monsters just seem like monsters without a specific weakness to them (maybe a blight weakness would be good for them?)