Like most AH games, ROR is notoriously simulation-heavy, while its cutthroat political gameplay had earned it the reputation of "a game designed for people who consider Diplomacy to be too tame". The gameplay occurs in turns, with each one divided into seven phases:
- Mortality Phase, where players draw chits randomly to determine if any of the senators in play fall over dead.
- Revenue Phase, where players collect income from their various offices and properties and redistribute it among members of their respective factions.
- Forum Phase, where players roll for Random Events and can expand their factions' rosters or boost their influence.
- Population Phase, where the HRAOnote mollifies any unrest in Rome to prevent a revolt.
- Senate Phase is the beating heart of the game, where players propose, vote on, and veto political actions like: appointing major officesnote and provincial governors, prosecuting senators for corruption, distributing state concessions, passing land bills to reduce unrest, raising Legions, and sending senators off with armies to fight wars. Oh, and they can try assassinating each other's senators at any point during this phase.
- Combat Phase, where players attempt to resolve outstanding wars with military force.
- Revolution Phase, where victorious generals must either relinquish their command or march on Rome in a bid to win the game.
Winning the game requires either a) rebelling against and toppling the Republic, b) becoming a Consul for Life, or c) having the most combined influence as a faction when the random events deck runs out. The game ends in a collective defeat for all players if either d) Rome must fight four or more wars at the same time, e) the people revolt, or f) the state treasury cannot pay for any required expenses — although if a senator is in rebellion when e) or f) occurs, his faction wins instead!
The 1990 original (a.k.a. the "Avalon Hill edition") went out of print after Avalon Hill was taken over by Hasbro in 1998, but in 2009, the Canadian company Valley Games purchased the rights to reprint The Republic of Rome and produced an Updated Re-release (a.k.a. the "Valley edition") as part of its Classic Linenote , featuring much more elaborate components than the original. Despite consulting by the game's original designers, however, the Valley edition came with a number of game-breaking errors, which, following the closure of Valley Games in early 2014, were left to be fixed by the community in unofficial errata and Living Rules.
The game contains examples of following tropes:
- Anyone Can Die: Literally, on any turn: At the start of each turn, numbered chips are drawn from a pot, and any senator whose number matches the ones drawn is immediately removed from play, regardless of other factors. Senators can also be assassinated or fall in battle, although you at least see those deaths coming.
- Artistic License – Politics: Real Roman Republican politics had been vastly more complex than how this game makes them look: there had been a lot more important political offices that were omitted for playability; the tribunes were major political figures in their own right, but because there were so many of them, the game instead represents them with common "intrigue" cardsnote ; and citizen assemblies have played a much more proactive role in shaping Roman policies from a certain point onward (though never really far enough to threaten a fall of the republic).
- Assassination Attempt: At certain points during the Senate Phase, players may attempt to assassinate any senator (even one of their own!), potentially removing them from play. However, a botched assassination carries severe penalties to the assassin's faction (notably, this is the only way for an entire faction/player to be completely eliminated from play before the endgame), making it a last resort.
- Cincinnatus: Senators appointed to lead military campaigns (especially those holding the Dictator's office) are expected to relinquish command as soon as they win — if they don't, they are automatically considered in revolt and must march on Rome.
- Civil War: This is basically the result of a victorious general refusing to disband his armies and instead marching on Rome.
- Corrupt Politician: Buying votes with gold is literally one of basic mechanics, and the game more or less assumes that every senator is corrupt by default: if they have held any major office on the last turn, they can be prosecuted for corruption, regardless of what they did. Other opportunities for corruption (and subsequent prosecution) include provincial governors taking their provinces' revenues for themselves instead of passing them on to Rome, as well as any senators receiving income from concessions (especially since concessions are often granted to senators by their own peers!). That said, prosecutions for corruption are just another form of vote, so if you are corrupt enough, you can buy enough votes to walk free.
- Dice Roll Death: During the Mortality Phase at the start of every turn, players randomly draw chits with numbers on them: if any senator in play matches one of the numbers drawn, they immediately die, with no way to protect them.
- Emergency Authority: A Dictator can only be appointed when Rome is in dire military danger, either fighting three wars at once, or a war so massive, it cannot be won by regular means.
- Highly Specific Counterplay: The Intrigue card "Mob Incited to Violence" may only be played to counter another Intrigue card played to counter a Tribune (itself an Intrigue card). Only one instance of this card exists in the entire game, but it functions mainly as a deterrent from messing with the Tribunes, since its effects are potentially brutal: depending on their luck, the targeted player may have all of their senators currently in Rome killed by the mob.
- High Priest: Pontifex Maximus is the lowest of the six major offices, but unlike the others, is elected for life, and has the power to appoint and to dismiss other senators as priests (boosting their influence), as well as to veto any proposal without a tribune. While it is an optional advanced rule, the game highly recommends using it.
- I Gave My Word: Breaking any promise made in front of all players (but not in private conversation) is explicitly against the rules, with certain very specific exceptions.
- Loads and Loads of Rules: The game comes with 26 pages of small-font, densely-packed rules governing almost every eventuality that can occur during play — and that is despite the combat rules having been massively simplified so as to not overshadow the core diplomatic gameplay of the Senate Phase.
- Military Coup: One way to win the game is to pull a Caesar, marching on Rome with loyal veteran legions and remaining undefeated until the end of your next turn.
- President for Life: If any senator reaches 21 Influence, a vote may be called to declare him "Consul for Life", which wins the game for his player if passed. If a senator reaches 35 Influence, they immediately gain the title without a vote, winning the game.
- Rabble Rouser: If a senator faces execution, his player may attempt to use his Popularity stat to rouse the plebs to his defense, effectively negating a successful prosecution — or even turning it around on his accusers.
- Random Event: Wars and other special events are drawn randomly from a period-appropriate deck of cards. At the start of each turn, dice are also rolled to see if some kind of bad fortune (like drought or plague) befalls Rome.
- RPG Elements: Every senator has an Oratory and a Military rating, affecting their performance in the Senate and in war, as well as Influence, Popularity, and Wealth, which go up and down, reflecting their political fortunes.
- Seduction as One-Upmanship: The Intrigue card named "Seduction", whose Flavor Text describes how the player's faction leader seduces another senator's wife. Gameplay-wise, this gives you an unopposed attempt to persuade any one other senator (except rival faction leaders) to immediately join your faction, weakening your rivals'.
- Shown Their Work: One of the game's three co-designers was a classical historian who had included four (densely-packed) pages describing the Real Life background of the historical periods and settings that inspired the game in its rule book.
- Sliding Scale of Cooperation vs. Competition: Depending on the chosen era, the gameplay skews towards either side of the scale. Most commonly, it falls under Dynamic Alliances (like most political strategies), but the Early Republic setting forces players to mostly cooperate against external threats, with competition over Influence being secondary to not losing the game for everyone; the Late Republic, on the other hand, is much more secure against "everyone loses" endings, with players free to engage in free-for-all politicking against each other. If any one of the players marches on Rome, the game even turns into a Team vs. Lone Wolf setup until the rebel either is defeated and executed, or wins the game.
- Torn Apart by the Mob: This can occur under a number of circumstances: during the Population Phase, if the Senate leader fails to placate the people of Rome, an angry mob storms the Senate, killing a random number of senators present; during the Prosecutions, an accused senator can launch an appeal to rile the plebs to his side — depending on how popular he is (and on a dice roll), the mob can rip either his accusers or himself to shreds (or stay uninvolved) in response; finally, there is a special "Mob Incited to Violence" Intrigue card, usable only when a player uses an Intrigue to counter someone else's Tribune, which punishes the former by randomly killing some of his senators for messing with the democratic process.
- Updated Re-release: Valley Games' second edition, which came out in 2009, added a number of fixes, such as the Era Ends event card (which is shuffled into the bottom six cards of the event deck and ends the game immediately when drawn, preventing the assassination free-for-alls that tended to plague the final rounds in the first edition) and the Imminent Wars track (which better paces out the incoming wars and gives players more time to react to them, preventing sudden game overs by a few bad draws).
- Veteran Unit: One of the regular legions that took part in a victorious or an inconclusive battle is upgraded into a Veteran Legion and henceforth counts as two regular legions for the purposes of combat resolution. More importantly to the political arena, a Veteran Legion remains personally loyal to the senator who commanded them in the battle where they got promoted, until either they get killed or disbanded, or the senator dies. A senator with loyal Veteran Legions does not have to pay for their upkeep if he marches on Rome, and any of his Veterans sent to fight him automatically defect to his side; on the other hand, if a rebel attacks Rome with Veterans loyal to another senator, the latter can freely decide whether they remain with the rebel or defect back to Rome.
- War Gaming: Downplayed, especially for an Avalon Hill game. Since wars have been a major factor in the history of Rome, they are prominently featured in the game, but the wargame mechanics are extremely simplified, with entire wars resolved by (if all goes well) one or two dice rolls during the Combat Phase. There are only two types of units (fleets and legions), needed to resolve naval and land battles, respectively, and even producing and deploying them is a matter of political negotiation in Rome. Since the game is ultimately a political, not a military strategy, the primary purpose of fighting wars is to boost (or to ruin) senator-generals' personal glory and fortune before they return back to Rome.