The gravity is too high. Otherwise, great game!
EDIT: it's ok for the gravity to be that high when trying to land, because it adds to the challenge. You could even make it so that turning the ship consume fuel, then you have to manage that resource if you want to do a successful landing. But I found it frustrating to always be pulled toward a planet outside of the view.
EDIT 2: maybe reduce the number of planets? That could do the trick. Anyway, I really liked your game. Can't thank you enough for doing a MacOS export. :D