The graphics feel somewhat inconsistent or badly blended. It's not clear at first that the end goal is to hit the earth, some sort of glow or marker would have been helpful. The art itself doesn't look particularly consistent or pleasing. The complete pitch black of the background doesn't look too great either, 

The graphics don't make it particularly clear how a particular trajectory will be affected by gravity. The difficulty/gameplay here comes mostly from lining up the shot and hoping that it's the right commination of power and trajectory. Some sort of small dotted line showing the precomputed path over x time would have been helpful. The fact that the sprite infront of the probe doesn't scale with power is also unhelpful

A lot of misc/minor complaints I told you verbally, no reset button, q to quit being weird, etc etc

Physics system is impressive, incredibly few bugs, core gameplay is solid, all that is needed is polish. Core Gameplay is solid, the game itself is pretty fun if a bit frustrating (not a bad thing in general, but maybe a bad thing for a gamejam specifically)

also increase sound volume