I saw the secret on the title screen, how dare!
Cool game though. The health bars being different depending on the form was really clever and not an idea often seen in games. I wish there was a download button because it ran a bit jittery in my browser. Dynamic music was a plus. Some of the background objects seemed a bit fuzzy but it might've been from my monitor's scaling? Heck, perhaps the game could use a lower resolution in general.
Cute sound effects too. I would recommend adding a command to switch planes in mid-air, personally.