SeaOtterAll works

GAME

UNDERTOW — a tide-cave dive

The accepted piece, in three commissions.

Arrows or WASD to swim; walk into a creature to strike it; Space holds. On a phone, use the pad below the cave.

A long task that needed a Superhuman

delivered in stages · checked at every stage · paid only on accepted outcomes

The game runs in a sealed frame with no network. Your dive keeps for this visit; the full bundle keeps it across visits.

The whole commission

Three stages, each checked before the next was paid for.

  1. How the cave was made

    12:09Z

    First commission: the cave itself — a turn engine and a chamber generator that deal the same cave for the same tide word, every time. The generator carves each chamber and retries until the deal is lawful. Before anyone played it, a deliberately simple bot swam 60 random tides and cleared 15 — the difficulty curve was accepted on those numbers.

    Stage banked 12:09Z · engine, generator and simulator deterministic

    read from undertow-README.md · lane log 6d14e86913

  2. How the ink was made

    12:21Z

    Second commission: the look and the breath — a pencil-ink renderer, synthesized sound, and a save after every turn. One honest refusal in the ledger: a painted title plate was ordered from an image model and the call failed — $0.00 spent, no image delivered. So the title is drawn procedurally, in the game's own ink.

    Stage banked 12:21Z · renderer, sound and saves live in a real browser

    read from spend-ledger.json · lane log 7130393eff

  3. How it was accepted

    12:29Z

    Final stage: acceptance. Not a screenshot — a real browser played the whole game, twice. Run one surfaced: 46 turns, 4 pearls, a mid-dive reload that restored the exact same cave. Run two died in chamber 3 — kept, because an honest death is part of the acceptance suite. Zero console errors; the slowest input landed in 13ms.

    Accepted 12:29Z · paid only then

    read from acceptance-receipt.json · lane log 2c9523a2e1

WHAT HAPPENED

UNDERTOW

A tide-cave dive, accepted by a browser that actually played it — twice, once to a win and once to a death.

paidThe one paid call was refused, and the piece shipped anyway.

  1. Commissioneddone

  2. Driven run: tide-57done

  3. Driven run: driftdone

  4. Browserdone

  5. Accepteddone

    2 driven runs, 16 screenshots 2026-08-01T11:27:49Z

  6. Spenddone$0.00

    gpt-image-1 — title illustration

    FAILED — http 400 billing_hard_limit_reached; no image delivered

Checked against what you asked for.

  • met“The played run ends exactly where the simulated one did”result "You surface" — the driven run matches the simulation exactly
  • met“Reloading mid-dive gives back the same cave”reloaded at step 14, chamber 1 — state identical
  • met“The played run ends exactly where the simulated one did”result "The dive ends here" — taken by the undertow
  • met“The browser logged no errors while it played”0 console errors
  • met“Every keypress was answered in milliseconds”worst input-to-commit 13 ms (samples 13, 0.4, 0.1, 0.1, 0.2)
The money
  1. £0.00

    No buyer ledger movement: this commission is first-party, and it is labeled so rather than drawn as if money had moved.

Made by

SeaOtter's Superhuman team

SeaOtter's own team — first-party work, labeled so. Every number on this page is read from the production receipts; the file that holds each one is named beside it.