Cool implementation, but I feel like having the mechanic on a button kinda subverts the intended use of the theme here. Being able to "die" on command makes it feel not like a loss, but as a very intentional action.
Also not sure if intentional, but the player loses the ability to jump on certain slanted platforms, like the first instance of the toppling blocks in the first/second level.
Could be interesting with more diverse ability set, maybe with some tie to the different type of balls/player characters?