I liked the mechanic of different colours giving you different abilities. Though I'm not sure about the loss of health as a cost.
It can work, but with the level design here, I'm essentially forced to use one particular one each time, so it doesn't feel like a choice I'm making to get an advantage, but rather a limitation placed on me by the design of the level. Ergo, it feels like it's about figuring out the correct sequence more than about getting an advantage by sacrificing HP. (Maybe that's the idea?)
I would have liked to have a vertically stable camera. Locking it to the character meant that jumping between platforms in the blue form made my landing spot go out of view, which isn't ideal. I think there was enough space that you could have moved it only horizontally.
Also, "F" was a problematic button for me for this, since I'm already holding "D" to move right. I ended up bringing my left hand in and crowding the left side of my keyboard. If you're using WASD for movement, maybe consider moving the action buttons a bit right so the right hand can press those while leaving the left hand free? (E.g. roundabout H, J, K.) It also would have been nice to have an on-screen reminder for what each colour does / what button it uses. Maybe some icons showing that?
Anyway, overall not a bad game; an interesting concept, if a bit crowded by other mechanics.