It's a neat little concept, felt a bit short though.

Quick thoughts

• I found it a little tricky to keep track of all 4 "universes" and the exact positions of platforms.
  • Perhaps consider adding "ghosts" showing where the other universe platforms are.
  • Or even reducing universe count to three or even simply two.
• I found a couple of the levels a bit frustrating. 
  • For example the rapid fall speed made 'the dropper' seemingly impossible until I realized I could simply go around the slopes. I'm unsure if that was intended solution or if I've cheated.
• The famicase's color scheme would have been easier on the eyes.
  
• Sound effects for various things (movement, switching universe, reaching cube etc) would help improve how the game feels.
• The character movement could use some improvement, like 'coyote time'. 
  • GMTK's Platformer Toolkit, is a great resource on how you can get platformer movement feeling good.
• Minor thing, but the uploads filename (and internal root folder) should match the game name. I downloaded a bunch of jam entries to a folder before playing them and was confused till I saw exe name.