A hundred and one koi
Along the journey, 101 koi cards wait at numbered ponds. This is how they are earned, what they do, and — because the game is free and we would like to be plain about money — what the one purchase in Koi Drift actually buys.
Earning a card
Each card belongs to a pond number. Reach that pond on the journey and the card is yours; there is nothing to buy, roll or open. The first cards come quickly — the shallows are full of them — and the spacing widens as the journey goes on. The last card, the Cosmic Emperor Koi, waits at pond 1000. He is the final card in the game. After him the cards end and the drift goes on: the ponds continue past 1000 for as long as you want to play, and the game calls that stretch Endless Drift.
The collection screen shows every card, the pond it lives at, and how many ponds you have to go. Cards carry a name, a rarity, a small story and two abilities described in the card text.
Guardians
Any card you have earned can be equipped as your Guardian. A Guardian swims with you and grants one run-power — a blocked predator strike, or an extra heart at the start of a pond, depending on the koi. When its power saves you, that koi rests for ten ponds, and you equip another. A player with a deep school of Guardians can rotate them; a player with one leans on it and then goes without. It is the collection’s only effect on play, and it is a real one in Watchers and beyond.
What is free
Everything you can play is free: all thousand ponds, Master, the Daily, Calm Drift, the languages, the music, offline play. Coins are earned by clearing ponds at par — under the tap budget the pond sets — and by crossing into new tiers, and are spent on helpers — Hint, Undo, +Heart, Safe Lane; there is no way to buy coins, and a pond cleared over par pays nothing. The first cards in the collection are free to hold as well.
The Android app shows advertising in two places. A rewarded video is offered, opt-in, when you would like a second chance or double coins; you choose to watch it, and you get the reward only when the video completes. And once you are past the first ten ponds of the journey, an interstitial advertisement appears occasionally between ponds — never during one, never in the Daily, the tutorial or Calm Drift. The web version at koidrift.com does not show ads inside the game.
The Drifter’s Pass
The Drifter’s Pass is the single purchase in Koi Drift. It is a one-time unlock — not a subscription, no renewal — bought through Google Play in the Android app. It does four things: it unlocks every koi card you have reached, all 101 as you reach them; it gives you a Guardian for every koi; it removes the interstitial advertisements between ponds; and it supports a one-person studio. It does not add coins, skip ponds, or make any pond easier. The journey is the same length for everyone.
If you reinstall the app, the Pass is restored from your Google account; the collection screen has a Restore button, and the contact page says what to do if it fails. The web version does not sell the Pass; it points to the app.
Why this design
A puzzle about patience should not be in a hurry to be paid. The collection is there so that the journey has landmarks — pond 88, pond 310, pond 1000 — and the Guardian is there so that a card you earned changes something. The Pass is priced as a tip for people who want the whole school on their shelf and the ads gone. If you never buy it, you have the same thousand ponds as anyone, and we are glad you are drifting.