THE STORY
40 missions, one galaxy, and a plot I have definitely thought about too much.
The set-up
It is the year 2340. The nine colonies of the Perseus Reach have not spoken to Earth in a generation, and the mail drones have stopped coming. You are Cadet Wren, the youngest pilot ever waved off the deck of the carrier Long Way Home, and your first patrol goes wrong in the very first five minutes. ~classic~
The middle bit (no spoilers yet)
Across 40 missions you fly for the Reach, then against it, then for a third faction nobody warned you about. There is a level set entirely inside a dead moon. There is a boss called The Ninth Moon that is not, in fact, a moon. There is a mission where your radio only plays static and the game never explains why, and it is the best thing Meteorhead ever did.
The soundtrack carries all of it. If you have not heard "Docking Waltz" at 3am with the lights off, have you even played it? (You can, on the jukebox back home.)
The ENDING
Ok. If you have not finished all 40 missions, turn back now. I mean it. This is the one thing on the whole shrine I keep behind a tag, because ruining this for someone would be a genuine crime.
Spoiler: the final mission, click if you have earned it
The carrier Long Way Home was never heading back to Earth. There is no Earth to head back to, it went dark decades ago, and the whole fleet has been flying loops around the Reach ever since, keeping nine colonies alive on a promise nobody has the heart to break. In the last cutscene Wren is offered the truth, or the promise. You pick. The credits song is called "Long Way Home" and it means something completely different the second time you hear it. I was NOT ok. best chapter in the series.