On the way, they do manly things like blowing stuff up, delivering one-liners and growing beards.
Alongside that, the games are about building atmosphere and drawing you into the moment, investigating abandoned warehouses and exploring a labyrinth of underground tunnels.
Besides dealing with the humanoid footsoldiers there is a great deal of focus on monstrous creatures you have to face such as the dinosaur-like Brumak (with a cannon on its back and chainguns on each arm), the crab/spider-like Corpser and the 'monkey-dog' Wretch.