The pistol is an energy weapon, but for some reason ejects shells.
The plasma gun and the gauss cannon share the same ammunition even though the gauss cannon fires flechettes and the plasma gun does not.
When Doomguy picks up the shotgun, he ejects a shell, yet the ammunition is at full.
The Prætor Suit is said to be impervious to almost any damage, yet the Player can be wounded quite easily.
The health station should not be able to walk or on an armoured arm.