Deathwatch (RPG)

Not to be confused with the titular Deathwatch.

Deathwatch is the third Fantasy Flight Games Warhammer 40,000 Role-Playing Game, and the first to focus on Space Marines - specifically, the alien-hunting Deathwatch stationed in the Jericho Reach. It's pretty cool; /tg/ uses it to make custom chapters.

System

I ain't no good with crunch. Someone else will have to fill this in.

The Chapters found in the PHB are the Ultramarines, Blood Angels, Dark Angels, Space Wolves, Black Templars, and Fantasy Fligt's own chapter, the Storm Wardens. Rites of Battle added the Imperial Fists; First Founding brought in the Salamanders, Iron Hands, White Scars and Raven Guard; and Honour the Chapter added a shitton of Chapters in the form of the Blood Ravens, Red Scorpions, Marines Errant, Flesh Tearers, Crimson Fists, Howling Griffons, Novamarines, Raptors and the Charcharodons. Of course, you can play as any chapter you like, thanks to the rules from Rites of Battle

Tactical Marine (all-rounder/command), Assault Marine (close combat jump troop), Devestator Marine (ranged fire), Techmarine (engineer), Librarian (psychic powers), and Apothecary (being a medic - do we have to spell it out?). Additionally, Rites of Battle and First Founding contain additional "advanced specialities", taken in addition to the normal ones: The Black Shield (effectively a Chapter rather than a Speciality; makes your chapter a secret), the Champion (a hero-hunter), Chaplain (buffing & "spiritual guidance"), Dreadnought (walking rape-machine), Epistolary (super-Librarian), Forge Master (super-Techmarine), Keeper (guy who has to guard rooms? I don't know), Kill-marine (solo operator), and Watch Captain (The Hero, and the guy who gets all the bitches).

Core Rulebook - The Player's Handbook, which also contains everything that the DM will need.
The Game Master's Kit - Not the Dungeon Master's Guide, despite the name. Contains a prewritten adventure and a DM's screen.
The Emperor Protects, The Achilus Assault, The Jericho Reach, Rising Tempest - example adventures and background information on the Jericho Reach setting.
Rites of Battle - /tg/'s favourite supplement, Rites of Battle is the biggest expansion to date, containing not only rules for creating your own chapter, the Imperial Fists, and advanced character creation, but also advanced Specialities letting you play as Chaplains,
Mark of the Xenos - Extra content on enemies and aliens.
First Founding - Finally getting around to adding the remaining four First Founding Chapters.
Honour the Chapter - A shitton of new Chapters for players to use, as well as rules for Successors that don't know their parent chapter or aren't closely linked to them.

Contains rules that actually encourage roleplaying
Lets you play as whatever Chapter you want
80% of the equipment you can give models on the tabletop can be given to your PCs here
Uses a similar system to the other 40k RPGs, allowing for some interchangeability of characters

To be expanded

The Ultramarines are once again shown to be the best Chapter ever at everything
Characters are so overpowered compared to normal humans, making it very hard to use characters in the other 40k RPGs

To be expanded