Curious effect with some killed enemies. Noticeable in areas like the start of Breakdown, with the zombie soldiers.
* Like the Playstation and Saturn ports, the [[Hell knight]] and [[Baron of Hell]] can hurt each other with their projectiles, and [[infight]] as a result, unlike the PC version where there is a hard-coded exception for them.
* Certain monsters are rebalanced with new behaviors or attack properties. For example, [[arachnotron]]s have a weaker twin [[plasma gun]] instead of a stronger single-barrel one; [[lost soul]]s are weaker with less health, but attack viciously, making them one of the most dangerous enemies; [[pain elemental]]s spawn two souls at a time when attacking, and the souls will cause massive splash damage to anything in the vicinity if they are blocked from spawning.
* Recoil effects when firing the weapons, e.g., being knocked back a few inches from firing a rocket.