Cool game and really good aesthetic (both graphics and sounds).
Despite being confusing at first I think it's easy to understand what the game is about. My only problem is that I couldn't find any reason to upgrade my engine/weapons, since I always found the same meteors and enemies (maybe if I had played more I would have found different elements). If you make some kind of progression (for example, harder meteors which give you more loot and more challenging enemies as the game progresses) it could become a really good game.
In any case, great job. I encourage you to keep going with the game development ^^