He’s just been duped into unleashing an alien horde from a mysterious underground shaft in a Marauder temple, deep underground on (in?) Mars. We never see any people, but we can hear them cursing Mason in the tunnels ahead as they flee from what he’s let loose from the planet’s depths.
The aim of this mission is to reach the surface in one piece. Even though Mason’s only just popped the cork on the alien nest, they’ve managed to get everywhere ahead of him and made a good start at destroying everything and wasting miners.
The aliens might have a bit of a Dead Space look to them, as does the darker, claustrophobic setting, but seeing as they generally go down easily the comparisons don’t last long. Red Faction: Armageddon is maintaining a heavy action vibe in place of any leanings towards survival horror. Your weapons will cut through most aliens so easily they’re not scaring anyone to be honest.
Early on, a fine variety of monsters can be seen gnashing their way towards you in the dark. Standard greenish ones scuttle towards you (leaving them open to a context-sensitive melee strike), red ones like to hang off walls and spit fire at you, while another will teleport around you and charge up an attack with red lasers warning you of its imminent intent.