I like the gameplay of switching ability. I think you can improve onthe wall slide because the player can get stuck for a while in the wall. I'm not sure if its a feature, but you can use one player to push the other player. Having some sort of tactics to switch players like for example when getting the mushroom to grow. One player to be able to jump should be on top of another player while jumping then switching again to another player to reach a specific platform. Overall nicely done.