I need to be honest. I had a lot of hope for this game, but I had to put it down before beating the first boss. The giant spheres that fly out at you are way too fast for me; I don't have the reflexes to dodge that attack. Then I started experimenting with the swap function. I assumed that when I used it, the two characters would swap locations, allowing me to dodge attacks that way. It wasn't the case. I think that if you let the characters swap location, the gameplay would become much more dynamic and fun. As of now, the game is overwhelming and takes place in a small arena without much breathing room or change of pace. Some players will be able to handle it, but I can't.
That being said, I feel that the concept is really strong. I love the art and music too. I hope you find a lot of good players who can tackle this. It deserves to go far.