Red Faction

Note: All weapon-related trophies count across all saves. If you want you can make a save near enemies, kill them, reload the save and repeat the process for every trophy.

Sometimes when you're attacking enemies, they will cower in fear and run from you momentarily, before attacking you again. They will also say something e.g. "Stop, I'm unarmed!". You have to kill 50 security guards (not mercenaries) while they are cowering like this for the trophy to pop. They do this pretty regularly so chances are you will get this just naturally while killing everything.