While the player demons are individually weaker than the Slayer-primarily because they don't have access to the same fountain of health and armour-they can conspire to harass and confuse, and even temporarily turn off the tap of pick-ups just when the Slayer really needs them. When the Slayer finds the Archvile, they often wish they hadn't its fire shield can be upgraded to reflect damage, while the double whammy of a flame lake and acid attack can leave the mighty marine with as many hit points as he has social graces. I prefer to present a smaller target as the Archvile, watching the action from the cover of some disgusting meat orifice in a forgotten corner of the map.
There's also the not-so-small matter of the jetpack, a whole new mechanic to manage while fleeing from BFG projectiles. It's harder work to get to grips with the Revenant its tendency to hover right in the middle of the Slayer's eyeline makes it juicy prey in the campaign, and the same is true for multiplayer.
