The game is pretty fun to play, especially level 4 and level 5. The puzzle feels really smooth and is very sastisfying to come up with the solution to it. The game graphic is put togethere pretty neatly.
However, I have to point out a few things:
1/ There is a general lack of polish. The character move sluggishly, no feedback when controlling the character, the wall and portal has no animation when going through. I will recommend checking out GMTK Platformer Guide on itch.io.
2/ Some puzzle, for example, level 2, requires a lot of movement time and in between actions. Since level 2 are too early for the game to be difficult.
There are other levels which absolutely stump me because the game hasn't properly introduce a mechanic yet, like in chapter 7. It took me 10 minutes to figure it out, after dying more than a dozen of time.
Overall, this is a cool concept that can be expand further. 5.5/10.
I hope this is a good learning experience for you.