This was a great entry. At first I didn't understand what I needed the flip for, but the level design is really good, so gradually as you're just jumping and pressing the flip button just because you realize the leverage it can give you and how and when it is necessary to progress. A very subtle feature but very rewarding when you can pull it off. Making your platformer unique without making the new feature feel like a pain to use can be difficult and you absolutely pull it off. That being said, you're right, I didn't finish the game because it got too hard for me. But I loved what I played!