The art is interesting, remind me of some retro games. the game mechanic is easy and self explaining.
Some improvement: 1. push box is very slow. especially in level 2 you need to push it for a long time. 2. the button to teleport might be not that accurate, sometimes I stand on it, expect it to transport but nothing happens. 3. I got stuck on level 4, when two character get far away I can't see either. not sure if it is a bug or intended that there are other way to solve it. If the later, I would suggestion add a text to let player know this is a wrong way to solve it, or stop player making two characters too far away.
All in all a good game!