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Into the Breach Mechanics Reference

What we're borrowing from Subset Games' Into the Breach — the game that proved deterministic tactical combat works.


Borrowed

Deterministic Combat

The core premise: no miss chance, no crit RNG, no damage variance. An attack that says "3 damage" deals exactly 3 damage minus DEF. This is Pillar 2 in its purest form.

Player skill is measured by positional decision-making, not by dice rolls. Losses are the player's fault. Wins are earned.

Our adaptation: We keep one deliberate exception — the Ninja-equivalent "Evasion" Defense aspect shows (?) on the timeline. This is a conscious design choice, not a rollback on determinism.

Telegraphed Enemy Actions

Every enemy action is visible before it happens: where they'll move, what they'll do, where it lands, and when. The question is never "what is the enemy doing?" — it's "how do I respond?"

Our adaptation: We add the charge time layer. ITB has immediate actions. We have spells that charge over multiple ticks, creating a new layer of interaction (kill/disable the caster before the spell lands, push them, body-block).

Vek Emerge → Downed State + Permadeath

ITB's "mech reaches 0 HP → pilot killed → permadeath for the run" is our model. We keep the 3-turn counter from FFT as a hybrid: unit goes down, counter ticks, then permadeath. This gives more drama and counterplay than ITB's instant death.

Roguelike Structure

ITB's island → mission → upgrade loop. Our 3-island structure, relic choices after each fight, and meta-progression between runs are all patterned on ITB's model.

Our adaptation: We add branching path choice (StS-style map) and node types (shop, camp, mystery, recruit) that ITB doesn't have. ITB's islands are linear; ours are not.

Tiny Grid → Big Decisions

ITB's 8×8 grid proved that a small space creates tight tactical puzzles. Our 8×12 grid is slightly larger (to accommodate 6–8 units in co-op) but the same philosophy applies: small grid, meaningful choices.


Adapted / Evolved

Push/Displacement as Primary Verb

ITB centered on pushing enemies into each other, into hazards, and away from buildings. Our Shove, Grapple, and fall damage mechanics are the direct evolution — but we add height as a damage multiplier.

Unit Roster

ITB: 3 mechs, each with a fixed weapon loadout.
Us: 3–5 units (solo) or 6–8 (co-op), each with 5 swappable Aspect slots. Same squad size constraint, vastly more build depth.


Deliberately Left Behind

ITB MechanicWhy We Dropped It
Building/Grid defense objectiveReplaced by unit permadeath stakes. No escorting buildings.
Fixed mech loadoutsReplaced by Aspect system. No two runs look the same.
No progression between islands (ITB is flat)We have the meta-progression shop + difficulty unlocks.
Time travel undo (entire turn)We keep single-move undo. Full-turn rollback is an ITB signature we're not copying — it doesn't work with charge-time spells.

Open Questions

  • [ ] ITB's maps were fully hand-crafted. We're procedurally generating. How do we validate that generated maps are actually interesting? ITB's maps are puzzles. Can a grammar system produce puzzles?
  • [ ] ITB had perfect information (enemy HP, attack patterns, everything). Do we ever hide information? Currently: almost never. The (?) dodge effect is the one exception. Are there others?

Markdown is the canonical GDD source.