Mission: Gem presents an interesting idea where the projectiles are items you must collect and store to score points. It makes the player balance between collecting gems for points and collecting gems for combat. It’s a novel idea, but the execution is a bit mixed. It works, but I feel it can be vastly improved with some touching up. The major thing this game needs is to allow the player to control how many gems they store. If I collect 15 pearls, I don't want to store all 15. Let me choose how many I can store, and how many I keep on me. I know that might remove some of the pace, but I think the benefit of that system outweighs keeping that.
I did have a fun time trying this though, and I would like to see this expanded upon if you do in the future.
Also, enjoy the small tip I gave you.