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Lab

Lab · Family game · 2026

Sudoku Versus

A live head-to-head Sudoku game. Same puzzle, two clocks. Play next to someone on one phone, or send a link and race on two devices. Classic is a clean race. Battle adds strikes, reveals, and an advertisement you can drop on their board.

Role
Prototype lead
Stack
Real-time · Private rooms · Battle items

URL

Idea to a link you can send

2

Players — not a lobby of strangers

3

Classic · Battle · Same phone

Live

Shipped. Play it.

Origin

It started as pillow talk. My wife asked who was better at Sudoku. Not theoretically. Who would win if we actually played. I built the game. She was better.

How it works

  1. 01Name and difficulty. Type how the other person should know you. Pick Easy, Medium, or Hard. Practice does not need a name. Hosting a room does.
  2. 02Same puzzle, two boards. Both players get the identical starting grid. Givens are locked. In an online match you never watch them type digits — you see their progress and their move count. That is the tension: you know they are close. You do not know which numbers they have.
  3. 03Play. Tap a cell, tap a number. Pencil marks candidates without committing. Wrong digits stay visible; you can fix them. On a phone, one board fills the screen. View opponent swaps to their grid.
  4. 04First finished board wins. Completing every cell correctly ends the race. You finished first → First. They finished first → Close. Practice cleared → Clean. Agents helped with mechanics, balance, and the real-time layer. Humans kept the veto on feel, fairness, and whether it was actually fun to lose.

Modes

Practice alone is classic Sudoku — no items. Pass the phone is two people, one device; the game tells you when to hand it over. Play with a friend is a private room: invite link plus a six-character backup code, live battle. I have a code is how a guest joins. It is you and one other person. Not a leaderboard of strangers.

Battle

Classic, plus sabotage. Finish a row, column, or box and you earn that strike. Spend it on their board: clear a row, a column, or a 3×3 of their filled cells — givens stay. Miss three times and they can earn a reveal: one of your empty cells fills with the right digit. Online battle starts with an Advertisement. Watch a short sponsored break to send it. They pause while it plays. When it lands, a 3×3 of their filled cells can clear. Battle is optional mean. The race is still Sudoku.

Outcome

Live at sudoku.leespringer.co. The dare got an answer. She won. The game stayed. A prototype you can play is a different artifact than a prototype you can describe.