As per the reply above, I first thought the bullet was the barrel and the muzzle flash was just clipping. In the future, finding a way to change that observation would be good, perhaps by moving the bullet further out and shrinking the size of the muzzle flash and/or turning the opacity down - they aren’t really that large too. For a low-poly game I was expecting the characters to match that theme too but that is the design choice of the game dev I suppose. Purple guy’s horns are really busy and blend in with that second-floor deck too much (especially at thumbnail size), so that is something to watch out for.
I really like how well the render came out, the guns look absolutely amazing! The muzzle flash also looks like real flame which is really cool. The bystander-citizens in the background fleeing in terror is a good addition that sort of hints to spontaneity/hectic-ness of the current situation. I can see why the client was happy with the result, it looks nice!