This is pretty low-tech: it's basically just a couple of robots that check PLAYERDIST to see if the player is within some distance of them when the player shoots. The robots "hear" the knives if the player is within 2 chars, the pistol within 5 chars, the shotgun within 10 chars, and a rocket launcher within 20 chars.

The presentation of this engine is pretty simple and I could see something like this being useful to a beginner trying to make a stealth game. This might warrant three stars if it looked nicer or if you could switch back to weapons you've already tried.