AUTO-DEMO RUNNING · TAP TO STOP

KooDeck

Five short games. The rules change without warning. How fast you notice is the whole point.

The signature read-out
chose A chose B no reward rule flipped

Every choice you make lands here as a tick. Tall means rewarded. The gold dashes are the moments the rules silently reversed. By the end you'll be looking at your own data.

Not a medical test. KooDeck is an educational game built on the reversal-learning paradigm. It cannot detect, screen for, or rule out Alzheimer's disease, dementia, or any other condition, and no score here means anything about your health. Concerned about changes in yourself or someone else? Talk to a doctor.
Before you play

Why flipping the rules is interesting

Research on Alzheimer's models found something unexpected: the ability to adapt when the rules change broke down before spatial memory did. Animals learned that one action earned a reward, the rule flipped, and healthy animals switched quickly — the model animals kept repeating the old action. Those same animals still navigated and remembered locations normally.

The brain signature was overactivity in the medial prefrontal cortex spreading into the striatum — the loop that lets you change your mind.

Source: Earth.com coverage of a Texas A&M study in Nature Communications, July 2026. Findings are from animal models and have not been shown to transfer to people.

What that means for these games
1
Four games test flexibility. Learn a rule, then get quietly betrayed by it.
2
One game is the control. Path Keeper tests spatial memory, which the research says should hold steady. It's here so the comparison exists.
3
Nothing is announced. No "the rule has changed" message, ever. Feedback is your only signal.
Read this first. This is a game, not a diagnostic. Scores swing with sleep, caffeine, distraction, screen size and practice — a single run tells you very little. Nothing here is medical advice, and no result should be used to reassure or alarm anyone. If you've noticed real changes in planning, adapting or memory in daily life, that's a conversation for a clinician.
Session 01

Your battery

Play in order — later games assume the earlier ones.

Nothing is saved. Closing this tab clears the session — download your data from the report if you want to keep it.

Run interrupted

You switched away mid-game

Trials kept advancing while the screen was hidden, so some of them recorded a response you never had a chance to make. Scoring that would be unfair to you and useless to us, so this run has been discarded rather than saved.

Everything you finished before this game is untouched.

Game complete

Session report

KooDeck is free and ad-free. Support the project →

Reminder: these numbers are game scores benchmarked against illustrative demo reference values, not validated clinical norms. They cannot indicate the presence or absence of any medical condition. Please don't treat a low score as a warning sign or a high score as an all-clear — for anything health-related, see a clinician.
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Testing

Demo console

Drive a simulated player through the whole battery so you can test the games, the raster and the scoring pipeline without playing for nine minutes.

Simulated player

Notices reversals within a couple of trials, ignores single misleading losses, strong spatial span.

Speed
Level
Length
Play one game manually
Console
ready.