The Shocktrooper is a new enemy in Doom II's expansion, Legacy of Rust. Here, it is an evil marine demon inspired by other evil marine monsters from mods like Scythe 2. It fires a plasma gun at a fast rate, but the speed of the monster is slower.
Combat characteristics
The Shocktrooper is a possessed enemy that is tougher and faster than the other zombies, reminiscent of the "evil marine" enemy found in some custom mods such as Scythe 2. It shoots the same plasma projectile as the player's plasma gun, as opposed to that of the Arachnotron. Here, its roaming sound is Quake II's Strogg guards' breathing noise. Like other former humans, it can be gibbed.
Tactical analysis
The Shocktrooper does not have an alert sound, giving the player no audio cue that a Shocktrooper has woken up. It moves fast and stops to fire a burst of three projectiles at the player, which can deal enough damage to kill a player at 100% health should all the projectiles hit. When defeated, its helmeted head pops up and slowly falls back to the ground; to fit with this animation, its death scream is abruptly cut short.
Unique among possessed enemies, it drops neither its weapon nor its ammunition, so players cannot gain a plasma gun or cell charges from defeating it. This is most likely due to the Legacy of Rust expansion replacing this weapon and ammo type with the incinerator and fuel.