Level design is creative, very enjoyable puzzle game I must say. The one big issue I found is sometimes colliders are bigger than heart itself which caused restart even though I haven't touch the black heart. I think for such shape there should be few colliders combine to match it. Anyway, for first game it is very good job, the most important, it's fun to play. As was mentioned earlier in the comments, consistent graphics design would give much better feeling. I feel from the game that you will be probably good level designer, focus on that skill in future games and keep going!