This game is pretty interesting and fun to play. In the starting, the sounds of the SFX are a bit harsh, the movement and the controls mapped are not too good, however, the game has a good point over retention on the basis of fun and progression. The powerups and the logic of the game actually work. So scaling that upon a higher base would really make this game reach its top spot.
I would rather say to focus on getting the player controls more fluid and smooth. It should be responsive and intuitive. From the other statement I mean, if you try to polish this game on a larger scale like not only fixing all the errors but also focussing on the Game Design, Game Mechanics, Game Theory, and all the other stuff that are taken care of while making successful Indie Games, then surely, this game would reach the top spot.