Pretty good game! Graphics look nice and clean and pleasing to the eyes. Sound effects and music got the job done. Controls were responsive.
The dynamic of killing the enemies for moon dust was cool, but killing them I found to be a hassle. If they were not on the same elevation as me, I found it nearly impossible to hit them due to the delay in my shot and lack of ability to control the height of my jump. Getting on the same elevation as them put me in danger, though, and the amount of moon dust I got per enemy was too small for it to be worth it.
I also had trouble with the camera. Often it would swing back to an area where there were no enemies, I would go back through, and the enemy would be right in my face hitting me. Other times, the camera would show no ground, making me think there was a pit, but when I fell, I just landed on ground.
Overall, you got the foundations down solid, and this game could really shine with a few tweaks. Good job!