For your first ever game you should be unbelievably proud! My first games were nothing like this!
The changing music between areas is nice, the colour theme as a way to play with the 'classic' pallete while keeping it limited was a really great and creative choice! The movement felt a bit slow and frustrating (Especially while backtracking).
The use of 'down' platforms to have the player discover what the blue power did without instructions was excellent level design (Though the blue power doesn't totally protect me and I got hit quite a few times while using it)
The room transitions could be jarring if you didn't quite make a jump, you'd quickly go into one room and fall back into the first.
The enemies (and myself) aren't super obvious when they take damage. The red boss in particular I was hitting for a loooong time before I realised it had a crit spot.
I got the red green and blue powers but couldn't find where to go from there (I found a shortcut left of the red power, so I assumed that red crate was supposed to be destructible?)
I managed to somehow knockback this enemy through a wall?
