Really nice puzzle game! Thanks! Ps: speedrun is possible in third level ... 2 boxes are enough to finish the game. 

The base mechanic of your game it's really cool, nice sound efects, cute pixel art but the character's walking animation doesn't feel natural I think it's because the head doesn't move at all in a walk cycle, and also regarding the shadow, I think the shadow should be visible only on the ground that means only the bottom side of the circle representing the shadow of the player, and also I think it shouldn't change when the player  is walking because if the light source is above his head the shadow stays the same. But overall I enjoyed playing your game, good job!!

Being able to preview the alternate dimension is a great touch

I completed level 2.

Really cool Dimension-shifting mechanic

The two different layers to the maps were well designed and the ability to preview the alternate dimension was a really nice touch. I loved the music and the fact that it changed along with the dimension. It sets a distinct mood in each dimension really well.

I found the controls unintuitive at first because I badly wanted to press W or Up to jump instead of spacebar. This is tricky because then I found that you use W/Up to climb ladders. I think it would feel more natural if you allowed W/Up to jump and perhaps when on a ladder, holding the key would make the player latch on to the ladder to climb it. Just my thoughts.

Nice job.

Wow! Fantastic mechanic. Nice job, very innovative