Builds & shop

Build names

The game-over screen names your build from its two leading families: the top family's adjective and the runner-up's noun, so three Frost cards and two Kinetic ones is a Frost Juggernaut. A single family is an Adept; no cards at all is an Empty Hand. A tie goes to the family listed first below. Each build name keeps its own furthest wave, best score and number of runs, so "my best Blazing Pyromancer" is a record you can chase.

Curses

A legendary from the Essence Shop comes with a curse — out of a Family Pack or from Transmute. A legendary in an ordinary wave's hand is clean. The curse is rolled when the card is dealt and printed on its face in red, so buying one is a trade you can read before you make it. The curse lasts the rest of the run, and two of the same kind compound. Each is a multiplier on something the game already reads — sized to sting, never to make a legendary not worth taking.

The Essence Shop

After every fifth wave the free card is replaced by the Essence Shop. Essence comes from every death, whoever or whatever landed it: pets, burns and a bomber's own blast all pay, and how much depends on how strong the enemy was. Unspent essence carries over, so saving through one shop for a legendary at the next is a real plan. Extra cards the wave owes you — Tithe, a boss kill's bonus — are still dealt as ordinary hands once you leave.

Essence: a kill pays by how strong the enemy was — a range rolled on each kill, from 0–2 for a Mushroom to 3–6 for a Brute (every enemy's is in the bestiary) — an elite rolls its range 3 times, and a boss pays 30–45. Small purple motes fly from the body to the counter in the top-right as it is paid (the same counter stays lit over the shop). The Taxed curse pays 70% of it, and nine cards deal in it. The shop is an ability down the left (the only place one is sold), a row for each of your two biggest families beside it — a boost and a pack — then Transmute, then Reroll and Leave. Packs are its only cards, and it is mouse only, like the card screen. A price is a number of units — an ability 2.6 — times the size of the wave you just cleared: income is kills and the kill count grows with the wave, so one curve keeps a visit worth about the same at wave 5 and at wave 40. A reroll costs 0.6 units, and 0.3 more each time in the same visit.

Essence cards

Blood Money — Paid in red. Kills drop double essence while you are below half health.
Bounty Hunter — Wanted, alive or dead. Elites drop double essence, and bosses half as much again.
Deep Pockets — Room for more. Kills drop 20% more essence per stack.
Dragon's Hoard — Sleep on it. The more essence you hold, the harder you hit -- up to +40% damage. Weighed against shop prices, so late-game riches count no more than early savings.
Essence Nova — Brimming over. Every 12 kills' worth of essence you collect bursts out of you, hitting everything nearby for 45 damage. Grows with the waves.
Interest — Savings grow. Every shop you open pays 15% interest on the essence you walked in with.
Jackpot — Lucky strike. One kill in twenty pays its essence six times over.
Spendthrift — Money well spent. Everything you buy in the shop makes you stronger for the rest of the run: +2% damage a purchase, up to +24%.
Tip Jar — The crowd pays up. Every combo tier you reach pays 2 essence for each tier you are on.

Above rare, essence becomes power, and none of these cards counts raw essence — a late run holds thousands, and anything paid per essence would run away with it. Dragon's Hoard weighs what you hold against shop prices, in price units (an ability costs 2.6 of them): +40% × (1 − e^−units/4), so holding four units is +25% and forty is the full +40%, at wave 5 or wave 50 alike. Spendthrift is the opposite build — +2% a purchase, up to +24% — and the two cannot be held together. Essence Nova bursts every 12 kills' worth of essence you collect (at that wave's average payout), for 45 damage (wave-scaled) within 3.8 m; an arc round the counter shows the charge. The damage bonus shows under the counter while you hold either damage card.

Family items

Beside the ability, the shop shows a row for each of your two most prominent families — the two you own the most cards in (a fresh run with fewer than two is shown a random one). Each panel is sold under its family's icon, the same icon every card of that family carries in its header, and holds two things: a boost (or, now and then, the Recombobulator in its place) and a pack.

• One boost — one of the family's own three (listed on each family's page), drawn at random from those you do not own yet; a reroll draws again. Each is bought once. They cost 2.2 / 3.2 / 4.4 units by their place, I to III.
• A pack — three cards of that family you can still take, and you keep one (a legendary among them comes cursed). One a visit per family; a reroll puts it back. 4 units.
• The Recombobulator, on 10% of visits (and of rerolls), standing in place of one panel's boost — every card you own in one family is given up, one copy at a time, and replaced by a random card of the same rarity from one other random family (the nearest rarity it has, if it has none left at that one). The boosts you bought for the old family move to the new one, first to first, second to second. A card nothing can take back — Twin Orbs, a Contract, or one something else depends on — stays. A legendary swapped in comes without a new curse: the one the old legendary brought stays with you. What it gave is shown before you go back to the shelf. 2 units.

Transmute

Transmute sacrifices random cards you own of one rarity for a choice of one card a rarity higher. Random on purpose: the cost is not knowing which ones go — and it takes two clicks, so it is never an accident. It never takes Twin Orbs or a Contract, or a card something else you own depends on (Freezing Shot while you hold Shatter); a stack goes one copy at a time. The same undo is what lets The Collector hold your cards and give them back.