Short little platformer game, nice.
To me the gravity mechanic was a bit confusing at first. I think I got the hang of it after a short while though. Other point of feedback: Jumping often felt a bit unforgiving: you really have to fully be fully on the ground to be able to jump. Often, platformers allow for a short time after leaving the ground to still jump (called coyote jump).
Other than that, the game is really polished for a 1 man project and only a week of work. I also found the changing gravity as a mechanic quite fun.
Overall a good job :]