If it's on the ground, you should get it. Repulsive, ugly, cannabalistic, evil beings have just as much right to be loved as heroic fighters. The operation of a weapon is a simple and obvious procedure. You never run out of ammunition, just grenades. No matter how long you fight, you can always fight again.
Ninjas are common, and fight in public frequently.
Whenever huge fat evil men are about to die, they begin flashing red or yellow. Although the enemy always has more aircraft than you, they fly in elaborate patterns which make it easier for you to shoot them all down. All martial arts men have rippling muscles and angry expressions. The enemy always leaves weapons or powerups lying around for no reason other than so their bitter enemy can pick them up and defeat them with it. If it blows up or dies, it was evil.