Wow, what an amazing game and concept! This will definitely be showcased in Mark's video. I read some comments and I want to say these 3 things to complement.
I think the movement is fine honestly, it reminded me of that Twilight Princess master sword puzzle and I believe is well in place for this puzzle game. But I do believe that the rooms could be switched around to have a more balanced difficulty. I got stuck on the same level that the other commenter said (the green room with the telephone) because I didn't realize you could retrieve the button on a different portal with the same color until I did it by accident (This could be solved with the solution someone else said of painting the letter on top of the pad). Also, I found a little bug: when I tried re-starting the room immediately after placing a letter on a pad, I re-started the level but I didn't get back the letter that I had lost in the game before. It wasn't a big deal though because I just re-started the game again and everything was fine, but I thought I'll let you know anyway in case you decide to keep developing this game (which I really think you should!).
All in all its a fantastic game with a fantastic idea and well designed puzzles. Congrats!