i just played this today and was thinking what's wrong with the controls today. this comment made me realize it was a slight input lag. i think games should immediately respond to input event even if there is an animation to be runned (except death/fail situations of course).
i'm not gonna rant about performance/optimization, since people already said that.
one of my problem was the main menu is too much generic. there is near perfect designs in unreal markeplace and artstation. @Hazardous i think you should implement a good UI template for menus. i personaly in love with UI of the Control game. (ref: https://interfaceingame.com/games/control/)
Overall, the game has a good future i presume. I hope this comes to Steam even as a early access title. I would definitely buy for supporting you.