I didn't really like your game, very sorry.
The challenges are pretty hard. 2 challenges that I could beat quite easily, another one that I understood thanks to a screenshot, and one that was really hard because the enemy is nearly invisible. Maybe this one renders differently in the editor or as a desktop export (which I prefer to provide just in case ; I know people prefer web builds, but I have some bugs that I'd like to fix).
There are no invincibility frames, so I get game-overed by being hit twice in a row.
I just gave up after that. I found this frustrating.