It took me less than 10 seconds into gameplay to pick up bullets for the (already existing) gun. Your comment reads as if you didn't try to play the game for more than a few seconds.
It's a fun little game; no need to be so smugly dismissive.
I made it a few minutes, I admit it was boring. That isn't my fault. In a better designed games these things would be more obvious.
edit: OK I tried it again, got the gun, it autofires which still isn't fun. If I actually got to control it and had less ammo it would be more challenging. If that's a possible mechanic I couldn't see how to activate it. Still boring.