Ultimate Gameplay Mod

A full gameplay rebalance for EU5 1.2.x. UGM retunes the values the game already runs on so the whole world plays a credible game: the AI fights and expands like a real rival, wars are decided by battles rather than endless sieges, the economy has friction so no power runs away, and populations recover from plague and war over generations. No new map and no overhaul. Every change applies to the player and the AI on the same terms.

Smarter wartime AI:
consolidates its armies, holds for reinforcements, tracks enemies through fog, builds fewer forts, and leaves less bordergore.

Battles over sieges:
field battles and assaults decide wars, not endless carpet sieges.

Mercenaries priced properly:
smaller hosts, real hire and upkeep cost, far less AI merc spam.

Economy with friction:
idle treasuries drain, the building snowball is flattened, food is tied to geography.

Slower population recovery:
plague and war take generations to heal, and disease still bites without emptying the map.

Stronger prestige and diplomacy:
prestige is a real reserve, Great Power standing is cleaned up, and rank-ups are reachable.

Playable Holy Roman Empire:
an enforced Landfriede no longer locks princes out of war for good, and a prince can defy it at a price.

Historical AI steering:
magnets, rivalries and truces nudge the map toward its real shape, with no buffs or penalties to any country.

Economy

• Idle treasuries drain (COURT_SPENDING_FRACTON 0.10 to 0.14); building snowball flattened (BUILDING_UPKEEP_FACTOR 0.20 to 0.22, UPGRADE_PRICE_MODIFIER -0.25 to -0.20).
• Large empires are less self-punishing (control threshold 0.95 to 0.90, monthly control decay 0.01 to 0.0075).
• Food tied to geography (market distance and local-reserve factors raised); thin pops promote again (0.5 to 0.25).
• Papal tithe cut a quarter (tithe_price gold 1 to 0.75).

AI at war

• Armies consolidate before fighting (merge 0.80 to 0.95) and hold for reinforcements (combat 24h to 48h, wider await and attach distances).
• Tracks enemies through fog (forget chance 1 to 0.5); builds fewer forts (budget 0.1 to 0.07) and leaves less bordergore.
• New AI Drive rule (default on, behaviour only): +0.5 aggression, wars about 8 months sooner.

Mercenaries

• Smaller hosts: max stack 100 to 80 (vanilla 150) and per-ADM host size 0.25 to 0.10, so even a rich minor cannot field a huge host.
• The AI leans on mercs far less: cost weight -0.22 to -0.45, merc loans 2 to 1, lower preference.
• New Mercenary Costs rule (default on): hire +25%, upkeep -20%, so a large standing host drains the treasury.

Forts and sieges

• Build cost roughly doubled (fort stone 2 to 5; stockade, castle and city walls raised) with upkeep added to the cheap tiers.
• Sieges about 20% faster (siege phase 30 to 24 days).
• New Levy Combat rule (default off): over-cap levies fight worse.

Population and disease

• Recovery slowed to a generational pace, about 200 years to undo the Black Death (peasant growth 0.0010 to 0.0003, with matching rebound).
• Disease still bites without emptying the map (rural resistance 0.10 to 0.05, global 0.05 to 0.02).
• Fewer revolts on newly conquered low-control land.

Prestige, Great Powers and diplomacy

• Prestige is a usable reserve (decay 0.01 to 0.005, larger event payloads) and pays more from battles (0.5 to 0.75).
• Rank-up walls lowered: empire 70 to 50, kingdom 50 to 35, duchy 25 to 15.
• Great Power standing no longer double-counts hegemons; union seniority can pass to an active partner.

Holy Roman Empire

• An enforced Landfriede is forward-looking: it bars new internal wars but no longer white-peaces wars already in progress.
• The Emperor can no longer spam single-war enforcement (cooldown flat 10 years, no rank reduction).
• New Defy the Landfriede action (default on): a member can break an enforced peace and keep fighting, staying in the Empire at a steep prestige cost and handing the Emperor a casus belli.

Religion, culture and technology

• Religion weighs heavier against culture; Humanism tolerance is a real choice (1 to 2).
• Technology diverges further across regions.

Historical AI steering (behaviour only, no buffs or penalties)

• Magnets, cages, period rivalries and start truces nudge rising and declining powers toward their historical shape, with no stat bonuses to any country.

Performance

• Built from defines and static modifiers with no per-tick cost; heavy logic runs on slow pulses, and it stacks with performance mods.

• The launch baseline still in force: AI reinvests instead of hoarding, mercenaries and over-limit forts cost more, great powers can emerge, religion and culture carry weight, technology spreads slowly, populations recover, integration is faster, plus tools (cautious march, vassal downgrade) and notification events.

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• EU5 1.2.x; requires nothing; achievements allowed on default settings.
• Save-safe: loads onto an existing campaign; Game Rules are chosen at New Game.
• Runs with the rest of the Ultimate Mod Collection. Conflicts with mods editing the same defines or modifiers; load UGM last. Not compatible with full overhauls.

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Part of the Ultimate Mod Collection: UGM (gameplay), UPM (performance), UVM (visuals), UCT (tools).
Feedback and bug reports are welcome.

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