Hi! Web seems to be all around rough with Godot, but I also should've probably preload the sounds. Not sure if that would've fixed it, but it's an idea.
Also, the colliders are perfect - so perfect in fact, that is becomes a problem, the obstacles are designed to instakill the player, but the waves are sometimes taller then the level floor, and hide the lower obstables perfectly. Because of the tight fit of the collision shapes, you collide with the like one pixel wide top of the stone, and die as a result. Not great planning on my part to be fair.
Hp matters against the enemies, they do damage.