At a certain point the amount of things on the screen starts to lag my game, maybe make it so that large amounts of particles combine or something like that? It made it so that I could not access the shop or the perks screen, the shop and perk screen would refuse to show any buttons.
Also, I was playing on another run with both monitors and at some point once it got onto my second monitor and moved towards the right of the screen. It then moved off the screen and made it so I literally could not see the window. I don't know if this is a monitor problem or something with the game.
More shop upgrades would be great.
The only perk I seem to be getting any real use out of is Billow, either I don't understand how to get the best use out of the other 2 or they just feel worse to use than Billow. More perks would be nice too.
The Smiley boss tends to get obscured behind the main window often, it makes this boss much more frustrating and tedious to fight.
Overall I think this game has great potential and just needs a bit of polish and optimization. I like how challenging it is and the boss fights are very cool. Music goes hard too.