Thanks for the feedback! I know I have to work a lot on the UI to add more info. It's just that I'm focusing on the gameplay, which is why it doesn't have SFX or VFX yet.
The idea with the slow tower is more damage for a lower rate of fire.
The store building is in case I make a bigger map later and can add a second store higher up, so the player doesn't have to walk back down again and again.
As for the controls, the game was originally point-and-shoot with the mouse, but I thought it could be more interesting to simulate an 8-button controller like old consoles, it was designed more for the boss arenas.