Level ideas! PLZ HELP

https://flowlab.io/game/view/1542101 Don’t mind the art, I am improving, that is a place holder, I guess. Anyway, I need new ideas for this game. It is supposed to be sort of a speedrun style game. Look at what I have in my game and recommend something new to add as an object, or some more level ideas for my game. Thank you in advance!!!

make it a boss rush game, kinda like cuphead but just the bosses
makes levle design simple