The name Rogue Trader refers to two different games associated with the Warhammer 40000 universe. The original Rogue Trader was the first edition of the Warhammer 40,000 tabletop game, while the current Rogue Trader (2009) is the second of a series of Warhammer 40,000 tabletop roleplaying games. While its sister game Dark Heresy casts the players in the role of Inquisitorial Acolytes and focuses on themes of corruption and conspiracy, Rogue Trader is a game of exploration, adventure, and the horrors of the unknown, following one of the eponymous Rogue Traders and his crew as they explore the uncharted depths of space for gold, glory and the God-Emperor. Something like a more Grim DarkStar Trek — or, as some put it, Mirror UniverseStar Trek.Tropes for the former can be found on the main Warhammer 40000 page; this page is for the latter. See also Dark Heresy, Deathwatch, Black Crusade, and Only War,Rogue Trader's sister games.
This game contains examples of:
Ace Pilot: One of the possible archetypes for Void Master characters (the others being Ace Helmsman, Ace Gunner, and Ace Sensor Officer). The Flight Marshal elite advance that Void Masters can take is unambiguously this.
Oddly enough, the core rule book has no rules for anything those piloting skills are useful for.
BFG: Your ship has guns that take a good seventy men to operate, fired in salvos of hundreds. The big guns need over a thousand.
Big Bad: Karrad Vall the Faceless Lord, and Morgash Kulgraz, Kaptin of Da Wurldbreaka are both strong contenders for being the ultimate Big Bads of the Koronus Expanse.
Bigger Is Better: A literal case with Ork equipment. As the quality of the craftsmenship goes up, so does the size and mass of the piece of equipment. With human manufactured items, the opposite tends to be true.
Car Fu: The Into The Storm supplement finally introduces official rules for vehicles and vehicular combat into the 40k roleplaying system.
Cool Starship: Naturally. If their ventures are profitable, the player characters may eventually find themselves in command of a Cool Fleet.
Gameplay and Story Segregation: The chapter specifically addressing Rogue Traders in the corebook paints a picture of the Imperium gifting each newly-appointed Trader with a flagship, which will "often" be a cruiser, as well as frigates, cargo ships, and tenders. The actual character creation rules provide for the Rogue Trader and his/her crew to start with exactly one ship and no more. And while it is possible to start the game with a full-scale cruiser for a flagship, it requires the players to cut out a significant amount of their starting Profit Factor to do so.
Genius Bruiser: The Seneschal career path (though based on their initial skill set and starting equipment, it's more like Genius Ninja).
Go Mad from the Revelation: There's only one Navigator power that all of them share. It's called The Lidless Stare, and it basically lets them open their third eye (and that's a literal one, not some wishy-washy metaphor...); if anyone looks into it, they see the Warp. This can be detrimental to your health.
This also applies to the narration for a lot of the more remote planets in the books, which contain many examples of Lovecraftian horror.
Insufficiently Advanced Alien: The Rak'Gol have human-level technology and widespread cybernetics use, but seem to be almost entirely mindless when encountered.
Kicked Upstairs: A possible (and apparently quite frequent) explanation for how a particular Rogue Trader got his Warrant of Trade: some very powerful people wanted him out of the way, but he himself was too powerful to just kill, so they gave him the Warrant to get him to take his interests elsewhere.
Large and in Charge: Ork Warbosses, particularly the aforementioned Morgash Kulgraz. Also Calligos Winterscale, propably the most powerful Rogue Trader in Koronus Expanse at moment.
Lighter and Softer: than the other Warhammer 40000 games, at least. There is sense of adventure, discovery and making lasting changes in a wide-open sandbox area of the galaxy that is free from large-scale wars or plots and conspiracies threatening to bring everything crashing down.
Lightning Bruiser: The Rak'Gol, again. They are surprisingly fast, hit very hard, and can take more punishment than an Ork.
Machine Worship: The Machine Cult of Mars, represented here by the Explorator career path.
Merchant Prince: Any sufficiently influential Rogue Trader is basically this.
Military Science Fiction: The Battlefleet Koronus supplement includes expanded rules for starship combat and rules for large-scale ground warfare, allowing the game as a whole to take on more of this flavor.
Power Creep, Power Seep: Rank 1Rogue Trader characters are significantly more powerful than Rank 1 Dark Heresy characters; in fact, they're explicitly the equivalent of Rank 5 Dark Heresy characters (of 8 max).
Theoretically, at least. However, in practice, using Dark Hersey characters in Rogue Trader is a bit unbalanced. Well-built DH characters quickly out-scale RT characters because of cheaper advances (usually 100 to 300 xp vs. 200 to 500 for skills, and 100 to 300 vs. 500 or 1000 for talents), a larger variety of options, and the fact that while RT characters start with 5 more points in all their characteristics, they only have 4 characteristic advances, whereas DH characters have 6 total (with Ascension).
Which does make a kind of sense. High level ascension characters are the most loyal, singularly powerful servants of the imperium short of the Astartes, and have been through constant high intensity missions whereas a strong rogue trader is a civilian that does not generally need to adapt to anywhere near that level of stress.
Punch Clock Hero: The Into The Stormsplat gives us the Kroot mercenary as a career option. Rogue Traders are one of the few Imperial servants who have sanction to deal with xenos, and that includes hiring of services. The Kroot are excellent trackers, spies, and close-quarters combatants, but their help is strictly mercenary. They can be trusted to uphold their word, but how determined they are to see their task through is heavily dependent on the remunerations they expect to receive, to the point that they can resist fear and pinning better if their current venture is potentially profitable enough.
Psycho for Hire: A perfectly valid career option, as the game's supplements allow the game to pick some alternate career options that turn the characters into this, but The Soul Reaver introduces a full career path that makes all of these look heroic by comparison, namely the Dark Eldar Kabalite Warrior.
Recycled IN SPACE: Nearly all the game mechanics are recycled from Dark Heresy. If you doubt this, compare the charts for critical hits or the names and descriptions of most of the talents. (Of course, since the games were designed to be compatible with and supplementary to each other from the get-go, this is hardly surprising.)
Screw the Rules, I Have Money!: Rogue Traders are allowed to get around a great deal of the regulations of the Imperium, essentially because they're some of the most wealthy and powerful individuals in the galaxy (emphasis on individuals).
In the lore, this is the entire point of licensing Rogue Traders. On the frontier they are much more effective than more official operatives.
Shout Out: The description of the Endurance Motivation ("You seek to endure, and, in enduring, grow stronger") refers to a line spoken by Dak'kon from Planescape: Torment.
There is also the characteristic given to Death World characters, which lets them take training with primitive melee weapons, to represent their experience fighting terrifying monsters with improvised or underpowered weaponry. Its name? If it bleeds, I can kill it.
The Hostile Acquisitions sourcebook brings us the "Reaver" career option, raiders who have lived too long on the edge of space and now live only for pillage and slaughter. The accompanying illustration includes a rather familiar brown duster. This may be the only thing ever to become Lighter and Softer when translated into the Warhammer 40,000 universe.
Space Is Cold and Literally Shattered Lives: A major danger of void exposure is your corpse freezing solid and becoming fragile within a minute of death. Inherited from Dark Heresy, though given the activities of Rogue Trader characters it's a more common danger for them.
Space Pirates: A common threat to Rogue Traders and Imperial shipping in general. Come in human, Eldar, and Ork flavors.
There are two types of human flavour: Organic Vanilla (they're in it for the money) and Mutant Octopus (Chaos pirates- they're in it For the Evulz). Oh, and some Rogue Traders do this, too.
Starship Luxurious: Things that can potentially be found aboard a Rogue Trader's starship include vaulted ceilings, barracks for entire regiments of ground troops, room-sized techno-pipe organs, gladiatorial arenas, factories, and full-size churches to the God-Emperor (some of which can detach from the ship proper and be air-dropped as prefab cathedrals on worlds in need of converting).
Too Dumb to Fool: A particularly messy variant. If a Navigator takes The Lidless Stare up to Master level, anyone who looks into their Warp Eye has to pass a Toughness test or die immediately—unless their Intelligence is less than 20. As a comparison, the minimum starting Intelligence is 27...
Worthy Opponent: This can quite easily happen in-game between PCs and other Rogue Traders, since while most of them are rivals, very few are outright enemies as Koronus is filled with forces that are openly hostile to all humans. The supplement Edge of Abyss actively encourages GMs to have their groups develop rivalries with, and seek to surpass the existing canonical NPCs.
Writers Cannot Do Math: Working from the numbers given for the dimensions and tonnage of ships, small raiders are about half the average density of balsa wood (Ork Brute Ram: 60 kg/m^3) while the largest bulk transports would blow away in a slight breeze (Imperial Universe class: 2.9 kg/m^3). Crew requirements have the same scaling problem (as well as being far to low for how the fluff describes living conditions, even on the smallest ships) while passenger capacities seem to be random numbers that don't increase with size at all.
You Lose At Zero Trust: If your crew ever hits zero morale they will turn against you entirely and attack any authority figure they can find. Considering that even a "small" Imperial craft has a crew numbering in the thousands this means that the players will at least lose their ship, if not their lives. The only other solution is to execute the entire crew... and you can't run anything without them.