Gray Mann has built an unstoppable automaton army with a single purpose: to destroy all things Mann Co. Luckily for you, the majority of this robot legion is equipped with basic weaponry that could never level an entire building. Unluckily, they also have access to giant bombs, which they’d drag through hell if it meant dropping one in a Mann Co. bombhole. And it’s up to you to stop them. And it’s up to a small cadre of Special Robots to stop you from stopping the regular robots. Here’s what we know about these Special Robots:

Mann Co.’s currently rethinking its “All facilities should have a bomb-shaped self-destruct hole” policy, but while that debate’s raging, it’ll be up to you to make sure those bombs never get there. Take down bomb-carrying robots quickly, though, because the longer they’re holding one, the more powerful they get. Worse yet, these upgrades stack.

Giant robots can be identified by the fact that they are giant, covered in thick, damage absorbing armor, and probably charging straight at you. Good news: due to their immense size, they move at half the speed of their regular-height counterparts. Bad news: their horrifying weapons are giant too.

Essentially a bomb on legs, the Sentry Buster will detect any sentry that’s dealing sustained damage to the Robot Horde, then initiate its deviously complicated protocol: run at the offending sentry and explode. Thanks to a design flaw, it takes the Sentry Buster a couple of seconds to arm itself—giving quick-thinking Engineers a brief opportunity to hustle themselves and their belongings out of range.