|"Hm, the main character's inner conflict is intriguing, a shame the author didn't expand on it more."|
In Black Crusade, you play as a Heretic, one who has forsaken the crumbling Imperium, either Human or Marine. The Marines are unashamedly better in combat, but Humans can mitigate this by fighting more cautiously- picking off a guardsmen here and there, as opposed to just ramming into combat. Humans can do a bit more out of combat than their superhuman allies: Hereteks, for example, can repair and improve arms and armor.
The system is built on d10's and d100's. D100's (rolling 2 ten-sided die, using one as the "ten's" digit and the other as the "one's") are usually used for stat-based tests, as stats are on a scale of 1-100. For example, to pass a challenging(+0) Strength test, I would need to roll lower than my Strength of 40, average for a Space Marine. Rolls can be modified for easier or more challenging tests, so a routine(+10) test would add 10 to the characteristic being used.
Combat takes place in structured time, with each character getting one round, in real time, lasting a few seconds. There are different actions that can be done within an round, like Aim, a half action, which improves the next Weapon skill or Ballistic Skill test by 10. A character may only use one "attack" type action per round, like firing a gun, swinging a sword, or using a damaging psychic power. Basic attacks, like firing a single shot or making one melee attack, add +10 to the characteristic, and consume a half action.
So, say I'm engaged in combat, and I want to whack someone with my power sword. I would spend my round by using Aim, a half action, and Basic Attack, another half action. Total, this adds +20 to my Weapon Skill test, so if I had a Weapon Skill of 40, average for a Space Marine, I would need a 60 or lower.
The odds, not just here, but throughout the system, come out pretty close to how they would in 40k, so if you're familiar with that system, you have a pretty good idea of how good weapons are. Like, don't bother using a laspistol on a terminator.
The Armory and Enemies sections are extensive, covering a vast range of enemies and weapons, from flintlock muskets to the Q'sal glass dagger, from a guardsmen to a Tomb Stalker, to a Dark Eldar mandrake- anything you don't find in the Bestiary is most likely in another of Fantasy Flight's 40k RPG's, and they can be shuffled between books with few issues.
In fact, the GM chapter has a whole section devoted to cross-compatability, if you want to play as a Grey Knight from the Dark Heresy expansion, in the company of Heretics, or have a rebel Psyker in the retinue of a Rogue Trader.
I like how item acquisition works. Rather than buying them with currency, a test is made against the character's Infamy stat, with modifiers depending on the weapon's rarity, any upgrades or downgrades, and quantity. For example, if my Infamy 40 character (as famous as the leader of a minor warband) wants one(+10) item that is scarce(+0), with an upgrade(-10). With the modifiers added together, he needs to roll a 40 or lower.
Playing as a Heretic offers great roleplaying opportunities- the only limits are what you set, and that of your character- there is no law that you must follow, no Imperium telling you where to go. The sheer variety of worlds that can be visited is fantastic: feral worlds, death worlds, bustling, dreary hives, anything. The fluff of the 41st millenium, arguably more interesting than the tabletop game itself, is the world that the players explore.
The game takes place in the Screaming Vortex, within which is the Hadex Anomaly. If you look at the map in the 5th edition rulebook, that's not far from Ultramar, the Tau Empire, and a Tyranid Hive fleet. There's also an ancient space bridge that takes a ship to the Calixis sector, if one wishes to visit the Eye of Terror. Like I said, the roleplaying opportunities of it are it's greatest strength.
A tip to any GM's, a Dreadclaw makes for a fantastic way to start a mission, thundering down from the clouds, then roaring back up to orbit when the mission is over.
If you're looking for a way to play online, with friends that have moved away or you don't see often, check out roll20.net.