Not bad at all, and since you did this by yourself, you should be proud. It works, it looks pretty good, and controls fine.
The potential for the swapping of movement is high, but I don't see it realized here. The levels were easy on their own, but once I grabbed the thing that made me fly, it trivialized the levels to the point where I didn't understand why I was able to switch. The switch seemed more like the goal to me than the actual goal. I would have liked to see some reason to switch to flying to traverse over something challenge, or switch to flying and then be forced to switch back, but that never happened. As it was, I switched to flying, and the level was a cakewalk. There were also several unintended paths that bypassed all the obstacles.
Still a great job, though. Keep it up.