Nice game. The visuals are simple but clean. The game is challenging, but I'm into it. First it feels like another game where you have 2 characters controlling by one input, but the the twist came out. Are in the same world, but because there is for example black background you don't see black blocks. I really liked where the characters were moving both in different directions. It made more deph to the game. But one thing that I would change are colliders on spikes. Now they are same size as the sprite, but it's better to have smaller colliders at things that can harm you and bigger at thing that can help you (coins, hp, checkpoint and so on)
But I liked the simplicity of this game. Good job.