So, I could explain a little more in detail what each event entails, without spoiling things of course.

The Nexus Reactor mission is basically a homage to 'Aliens'. Spooky corridors, dimmed lights, endlessly repeating emergency voice in the background, fast and dangerous Mordrem creatures. 

The Doral Recruits mission is all about diplomacy, and maybe a few bar-fights. Convince a couple of Guardians, smack some lazy soldiers across the face, and maybe... just maybe topple the city-state regent to liberate the normal people who are suffering there! Just maybe, no big deal.

Hammer of the Army is all about ass-kicking right off the bat, and whatever other trouble might happen on the frontlines. If you enjoy writing a lot of combat scenes, this is for you.

The Kinabalu Eidolon mission is more about the spiritual side of things. Talking with locals, searching for signs, running into a cult or two, and then (maybe!) the Eidolon itself. It's a rumor, after all, it might be total bogus.

[@Ozerath]
Ah, I remember that one.
Still time left to decide!

[@Anima]
Added!

[@FantasyChic]
Not alone! There will be a few with you.