Great game! the artwork is really impressive! This mono color pallete really do make it seem like two totally different dimensions alltogether!
I would consider to make the controls a more intuitive. Such as using spacebar or even W to jump. Also, in some stages, the boxes that press the buttons would get stuck when swapping dimensions. Since we don't have a way to pull them, they get cornered into the walls, The only way to fix it is resetting the whole stage which can be a little frustrating.
at one time, I swapped dimensions and the box overlapped with the red dimension and got destroyed. That's great that you implemented that, great detail to attention, but then I realized I destroyed the box... forever. A box respawn would be great to fix all those issues without resetting the stage!!
Other than that, I had a really good time playing it!