It may only have been a short little game, but for what there was I enjoyed it! I liked how simple the game was, and how quick it was to learn too, and the difficulty was nice and challenging as well - easy to learn, hard to master. The jumping did feel a little off to me though. Maybe the hitboxes were off? I can't quite place what it was, but it threw me off a bit. The graphics looked good, although they were quite noisy - maybe reduce the dithering in the background a little? Some more visual feedback would've been good as well, like some sort of indicator when you hover over the missile. The parallax effect was very nice though and the colours worked nicely too, so it was a visually pleasing game! It was a fun time playing it, so nice work!
Oh, and one other thing - the game did crash for me once after leaving the how to play section, and wouldn't reopen, so I had to download it again. Maybe it was just on my end, but if you come back to it that's something you might want to fix :)