Nice little puzzle platformer. I do really like the idea of limiting how many times the player can jump, though I do wish there were a way to get some more as we play; maybe string a few extra hearts off the beaten path if a player is stuck repeating a particularly challenging level?
Also, I'd really enjoy seeing this concept with levels that challenge players to make as few jumps as possible, rewarding them for hanging on to their supply of lives (i.e. jumps) and make them feel smarter and more skilled for doing so (for e.g. look up challenge videos of platforming games where lets players challenge themselves to beat a Mario game without using the jump button).
Also, being down to one life just means that as soon as I jump, it's an instant death. I'd prefer it if instead, I died as soon as I landed back on the ground after jumping or if I tried to execute a double jump in mid-air. I feel like a lot of badass "clutch" moments could occur from that possibility of "They only have one more jump, will they make it??"