Great game, and great idea, I wish the swaping was tied to a different button, rather than the shooting being on the same. I don't know if it was intended but sometimes the checkpoints fail and you are sent back to the beginning, which can be very annoying. I also wish there was a way to tell what would be different when you swap. good job!
Thank you for playing my game!
About the checkpoints' failure: If you hit a checkpoint and was sent back to the beginning, it is most likely because your life is being used up. Your life count is visible at the top left of the screen. If your life is not being used up but was still sent back to the beginning, please make a reply, we will figure something out.