fixed crash from dying to a space slime

fixed space slime's health bar moving around

fixed crash and visual bug from the "inconsistent" gun

fixed the black and red gun not healing the player, also nerfed the healing from 5 HP to 2% of current HP

fixed the "cluster coating" artifact not working on impact

fixed some weapons not mirroring properly

bought artifacts are now removed from the shop's item table

removed a key event used for debugging an unused feature