[x2495iiii]

Resident Penguin doesn't use bullet collision, actually. It uses two dummy objects on either side of the penguin to determine roughly which enemies are directly in front of it. Then it highlights one of those enemies. If an enemy is highlighted when the gun is fired, the hit is automatic.

That old top-down shooter I made a little after RP uses bullet collision, though. The problem we consistently ran into was that bullet collision is inaccurate unless everything in the world has accurate collision detection, which isn't true.

Still, good job for the OP for sharing his methods with the community. Thanks!