How to play

• Wait for the red screen to turn green — the delay is different every time.
• Click the moment it changes; the time in milliseconds is your result.
• Clicking while it is still red is a false start and the attempt is lost.
• Five attempts make one run.
• Your score is the median, which is far more honest than a single best click.

Tips

• Rest your finger on the button instead of holding it above the screen.
• Look at the whole screen, not one point: peripheral vision notices change faster.
• Do not try to predict the moment — anticipation produces false starts, not records.
• A human reaction to light is about 200–250 ms; below 150 ms is usually a guess.