Nice expression of the invincibility theme and a cool little platformer! I always enjoy when these kinds of games encourage you to go fast, so I personally liked the timer. I will say I felt like the player movement/controls could use a bit more fine tuning if you keep working on the game, I enjoy going fast, but movement speed and jumping had so much sudden velocity that I found it pretty hard to control at times.
Other things I liked: It felt really satisfying to bust through the blocks. The levels, especially the early ones, felt good to play and bounce from potion to potion. Having a grade system with up to three stars was really fun and encouraged replaying levels. You mentioned you used other assets and that anything bad was yours, but I didn't see anything that stood out in a bad way, the visuals were coherent and worked together well.
Nice work, you have a fun game here!