Quick writeup on this one because I just finished it.
It was a fun game, overall. I didn't pay a lot of attention to the story, but it seems you are tricked into triggering an infestation of necromorph-looking monsters into the Mars colonies. You need to survive and then kill the invasion, as well as some cult dudes who support the monsters.
The structure of the game was a bit of a disappointment after Red Faction: Guerrilla, which had a fun open world where you could destroy tons of buildings. Armageddon has fun destruction, but not at the scope of its predecessor. This was more of a linear shooter with a bit of destruction.
The weapons are fun and you have a variety. My favorite was