Nice idea to have these different forms of a character and being able to switch to get to different sections of a level. Personally I think the green guy is kinda overpowered haha.
What would have enhanced my experience though, is if you would have made the switch between characters accessible on a hotkey, because sadly, there is a few issues with this. I got stuck too often when I am in the wrong form at the wrong place. Also sometimes I am in a screen but the camera is still looking at a different part of the level.
But overall a nice little enjoyable concept!