The journey, tier by tier
Deep Drift is a thousand numbered ponds climbing through eight tiers. Each tier introduces one idea and then gives you thirty ponds to make it a habit before the next. Here is what each one is for, and the single thing to practise there.
Stillwater
Small, quiet ponds with a generous clock and no predators. The rule is the whole game: tap a koi only when its full path to the edge is clear. Bends arrive partway through the tier so that the idea of an exit that is not straight ahead is learnt early. Practise: tracing the path with your eye before your finger moves. Everything later is this, faster.
Currents
More koi, some now bending left — the mirrors. A watcher appears on one lane, and the lane breathes from orange to red, but here it only warns: crossing on red costs nothing. Practise: watching the lane change colour and noticing how long orange lasts. This tier is thirty free lessons in the read that the rest of the journey will charge for.
Watchers
The watcher strikes now. You have two hearts; a strike costs one, and a second strike ends the pond. Pause koi begin to appear toward the end of the tier — the ones with the pause mark, which stop at their corner and wait for a second tap. Practise: the two-part look — is the path clear, and what colour is the exit lane right now? Equip a Guardian koi from your collection if you have one; several block a strike or add a heart.
Hunters
The same rules with more of everything: more koi, a higher share of bends and pauses, and by the end of the tier a second predator with its own lane and its own clock. Practise: holding two cycles at once. Park a pause koi at its corner while one lane is red and release it when the other turns orange.
Crosscurrents
Denser ponds, predators still hunting. The lesson is patience under pressure: there is almost always a koi that can move safely somewhere on the board while the lane you want is red. Practise: the detour. When your planned move is blocked by a red lane, make a different safe move rather than waiting and losing time.
Riptide
Three predators and a faster cycle. Pause koi are common. Hearts still carry you — a strike costs one, not the run — but the margin for a misread narrows. Practise: tapping on the change to orange rather than in the middle of it. The middle of orange is closer to red than it looks.
Tides
More predators, faster still. Every idea from the earlier tiers is present at once, and the ponds are the largest in the journey. Practise: clearing outward — the koi nearest the edges first, to open lanes for the ones behind — and spending coins on Safe Lane only when two lanes cross the last exits.
Master
Endless, and unforgiving in one specific way: there are no hearts. A single red-lane strike ends the run. Nothing else changes, which is the point — Master is the journey’s rules with the safety net removed, and a run there is the clearest measure of how well the read has become a habit.
How difficulty actually moves
Difficulty in the journey is a fixed function of the pond number, the same on every phone and at every playing speed: pond 40 is pond 40 for everyone. Inside a tier the generator’s parameters — koi count, the share of bends and pauses, the clock, the number and speed of predators — slide from the tier’s opening values to its closing values across its twenty ponds, so there are no jumps, only a slope. Because every pond is built from a seed, two players at the same pond number get the same pond, and a pond you cleared can be replayed exactly. The tier boundaries above are where new ideas enter; the slope between them is the same for everyone.