Having specific horizontal/vertical controls in space feels weird, always expecting for it to be relative (like a spaceship) before realizing it isn't. Tapping is also an odd choice - I was trying to hold the keys down at first before re-checking the readme and saw that it's tapping. Ended up growing so big I could barely see anything even with maximum zoom out. Also, I like that you can crash into the moon as well.
Other than that, didn't really have much performance issues.