I really liked this game. On of the best I have played so far.
Fun game idea with a good implementation of the puzzle mechanics.
The art style was nice to look at and the music and audio fit the overall theme.
You did a good job of teaching the player the game mechanics, something I messed up in my game. Very important stuff :)
As an improvement, I think it's better to use the S key to teleport because it gives a nicer flow when moving between areas. Also, you don't get teleported back if you come from another area and stand on the new teleporter for a half a second too long.
I also noticed two minor bugs:
First, sometimes you cannot walk over blocks and you have to jump over them:
Second, the hitbox on doors seems to be a little bit too big:
You can also softlock yourself sometimes and have to reset with R.
I don't know if this is intentional, didn't bother me.
All in all very good work. Keep it up :)