Breakthrough Tiers - Heliomance/Uncharted-Horizons GitHub Wiki
Discovery Mechanics · Design document §1.2
| Tier | Its idea | Odds of occurring in its moment | Design Intent |
|---|---|---|---|
| CORE | Occurs as soon as the breakthrough is discoverable | Certain | Foundational discoveries. Every civilisation will discover these through normal play. A player funding the right Focus Area will always get these eventually. |
| STANDARD | A window of half its era | 85% | Historical discoveries — things that happened in our world. Most civilisations will discover most of these. May have environmental prerequisites (e.g. coastal access for seafaring, iron deposits for iron smelting). A missed STANDARD idea comes back if anything waits on it. |
| UNCOMMON | A window of its era | 40% | Moderately hard: discoveries that turned up occasionally in history because they were difficult — not because something better pre-empted them, which is a Competing Solution (below). May have environmental prerequisites. A decent number of civs will discover some UNCOMMON breakthroughs, but not every civ will discover every one. |
| RARE | A window of its era | 10% | Speculative or alternative-history breakthroughs — things that could have happened but usually didn't. Won't show up every game. When they do, unlikely to be discovered by more than one or two civs. Should be exciting: powerful benefits or entirely new play styles. But the game is always completable without them. When a RARE breakthrough gates a chain of related discoveries, the follow-ups in that chain should be STANDARD — once you've found the path, you can walk it. |
| UNIQUE | A window of its era | As STANDARD for the first; lower for each UNIQUE already held | Cultural identity breakthroughs. Shape your civilisation's playstyle. First civilisation to discover claims it; all others permanently locked out. Always have prerequisites — usually environmental (terrain, biome, geography) plus at least one breakthrough prereq. Must push the player toward a playstyle by making the prereq conditions more valuable. A UNIQUE requiring desert should make desert tiles better; one requiring mountains should reward mountain expansion. Your combination of UNIQUEs defines your civilisation's identity. |
Since CORE breakthroughs reveal themselves once eligible (§1.4), the tier is reserved for what the familiar game cannot function without. A breakthrough is CORE if it (1) unlocks a focus, or is required to make one available; (2) reveals a strategic resource; (3) grants a building or improvement every Civ V city builds — Monument, Granary, Library, Market, Temple, Walls, Aqueduct, Colosseum, Harbor, Workshop, Castle, University, Bank, Public School, Factory, Hospital, Research Lab, and the Farm, Mine, Pasture, Plantation, Quarry, Road, Railroad and Fishing Boats; (4) lies on a victory path (the Apollo Program, the spaceship parts, the United Nations, the Utopia Project) or opens the seas; (5) grants the defensive backbone — the main infantry line of each era and the first archers; (6) is a decisive experiment; or (7) is a required prerequisite of anything CORE, so that nothing CORE ever waits on an idea that may never occur. Everything else is STANDARD or rarer: specialist units, navies, air forces, wonders and flavour keep the uncertainty. The existing CORE nodes of the FTL path were left unchanged, so the endgame puzzle neither gains nor loses certainty.
The first UNIQUE idea a civilisation can claim has the same odds as a STANDARD one. Each UNIQUE it already holds lowers the odds of the next: roughly, the second is moderately less likely, the third noticeably, the fourth quite unlikely, the fifth and later very unlikely (values for tuning; the simulator stands in a flat 6.5% for every UNIQUE). This naturally limits civilisations to 2–5 UNIQUEs depending on luck and investment, and creates strategic tension: do you pursue a fourth UNIQUE or focus those resources on advancing your existing strengths?
- Environmental prerequisites: Most UNIQUEs require specific terrain, biome, or geography. This ensures they naturally gravitate toward civilisations whose starting position fits.
- Feedback loops: The benefits should amplify the value of whatever the prerequisites require. A desert UNIQUE should make you want more desert.
- Buildings and units: Every UNIQUE should grant at least one special building, unit, or ability that other civilisations cannot access.
- No UNIQUE is required: The game is always completable without any specific UNIQUE. They add flavour and power, not necessity.
- Quantity: There should be enough UNIQUEs that every civilisation in a full game reliably discovers 2–4 that fit their situation, with many left unclaimed.
CORE breakthroughs appear reliably — the player can count on them. STANDARD breakthroughs appear in most playthroughs; occasionally one's idea never comes, creating mild variation between games, and if other work needs it, it turns up again. UNCOMMON breakthroughs are where real divergence happens: two civs investing equally in Mechanics might find different UNCOMMON breakthroughs, leading to genuinely different technology paths. RARE breakthroughs are surprises — a player who sees one should feel lucky, and the breakthrough should be powerful enough to reward the investment that led to it.
A breakthrough can be absent from a game in only two ways, both fixed at world creation by the World-Truth ruleset derivation (§7.0): a Removal Truth deletes it (no gunpowder, no fossil fuels), or a foundational axis leaves no room for it — the branches belonging to the values this world did not draw never exist, so an elemental world has no Nuclear or Quantum Physics, a germ world no Humoral Medicine. A third group is present but may dead-end: the rival theories a decisive experiment adjudicates (the rival theories of heat both exist until the Joule Laboratory reports; then one validates and the other dead-ends), and frontier breakthroughs whose axis value refuses them (Nuclear Fusion can be researched in every atomic world, but in an FQ2-Impossible world it never ignites). A dead-ended breakthrough yields its consolation and its report, and obsoletes nothing. Within what a world permits, a player who meets all prerequisites always has a chance at any breakthrough, and the tiers set how good that chance is: an idea that does not come in its moment is lost to that civilisation unless diffusion brings it, rediscovery returns it (STANDARD ideas that other work waits on) or, once Revealed, an Endeavour completes it.
A breakthrough's price may carry multipliers keyed to the world's Truth values. The rule for when to use which lever: if a breakthrough's physics is impossible in a world, remove it (a continuum has no photon to count, so Photonics never appears there); if it is merely harder, multiply its price (a pocket-sized resonance computer is possible but slow to reach — Miniaturisation costs ×2.5 in Elemental worlds). A multiplier applies only to a breakthrough that exists in more than one kind of world — it expresses how much harder the same thing is here; a breakthrough exclusive to one world simply has its price set where it belongs. The detour margin on a Competing Solution's alternative (×1.5 while its primary exists in this world) is this lever too. The multiplier is data on the breakthrough (costModifiers: {truth value → factor}), evaluated once at world creation, and it is the finest balance lever the design has: a world can be made to feel the difficulty of a path without losing the path. Engineering rows of the FTL signature fields carry fixed multipliers (2.5×, capstones 4×; §4).
What a civilisation already knows can carry it partway: the Antikythera and Clockwork chains toward the Babbage Engine, the Atmospheric Engine toward the Steam Engine, Mycological Knowledge toward Antibiotics, Bio-Organic Synthesis and Biomass. The rows write these as "×0.5 (a multiplier, §1.2)"; each is applied as a head start, the meter starting half filled when the breakthrough comes under study, not as a lower price. Both save the same Insight, but a head start is the clearer promise ("starts half-studied" holds whenever the breakthrough opens, early or on time) and momentum favours the line from its first turn.
When a RARE breakthrough serves as the gateway to a chain of related discoveries, the follow-up breakthroughs should be STANDARD (or occasionally UNCOMMON). The principle: the hard part is finding the path; once you're on it, you should be able to walk it. A player who gets lucky enough to find a RARE gateway shouldn't then wait on three more unlikely ideas to benefit from it.
Current RARE gateway chains: