Nice little game!
It's hard to get used to the controls at first, mostly the fact that when you reverse the gravity, you also invert the movement axis, but it's still enjoyable to play.
I feel like the looping mechanic is working in a platformer game, but the gravity switch system actually makes it hard to do a loop to kill enemies (also the fact that there's a very limited size between pins doesn't help either). Maybe a platformer with no gravity switch where you have to perform precise jumps and place pins on the way would've been interesting? Hard to tell, but I hope you get my point. The idea is very interesting anyway!
I enjoyed playing the game overall :)
Congrats for the entry!