Nice idea, honestly.
But, as for now, I can run off the level and never return. And for some reason I couldn't jump to the second platform due to some collider issues, I guess.
However, if make gravity higher (so we fall faster), adding particles and effects to the shots would be decent. Especially if change the level a bit to include sort of vertical platforms as well. Sound also lacks a lot to me :( Ricocheting is a nice feature, but it seems to be sort of endless—maybe add fade out for it or changing directions randomly?
Do you think to add crouch to the player? Also, I guess the game would benefit from some animations and melee damage, maybe.
As said, hard to rate an empty game now if you don't see it fully developed yet, but I believe that it might be interesting to play with a friend. It gives me vibes of PocketTanks. Maybe you will find it useful as a reference for weapons or level destruction (if you have time) <3