This is a really neat concept! I did find it a little confusing to tell objects apart sometimes - after a while I couldn't tell the different parts of my ship apart anymore - so I agree that adding some different colors would hugely aid readability (the simple geometric style by itself is fine, though, and can look quite nice!). Sound effects would also make the gameplay a lot more satisfying, even without adding anything else. In general, pushing the juice on this would add a lot; this is already a strong base for a game, and it would help take it to the next level. A score counter would also be nice, to add a sense of progression. Good work on this overall!