I think I just echo what is already said, but might as well list them out: - Enemies have no telegraphing on the attacks. - The attack is very weird, I honestly thought it was a melee attack for a while, and then I just had a hard time judging the distance of the attack. - Transforming feels a bit weird, I'm still not sure if its when the bar is full or if it needs to get past the 80% thing and you/the enemies do something. - Audio would also help, but seeing as this is your own engine I can understand if you haven't implemented that yet.
Beyond all of that, the game was actually pretty solid. It might just be me, but I genuinely had a lot of fun running around and murdering everything. Visuals were also very good. Good job!