Fun concept! I found the player a little hard to control, but once I got the hang of it, it got pretty fun! I also found the last level to be unclear about what was happening, so I'd already lost my opportunity to get extra hearts by the time I realized what was going on. I would've either made the player not get permanently stuck, or given them more of a grace period through the level design before the fatal moment. A lot of potential for this idea though!