Pulse — free browser game

Pulse is the rhythm cousin of classic estimation games: a small ECG monitor opens on screen and the patient's heartbeat is drawn as a green wave scrolling from right to left. Each beat appears as a sharp 'R spike' on the wave and a red heart flash in the top-right corner — use either cue to keep your count. When the round window ends the trace freezes; enter the number of beats you saw using the stepper below and confirm with Enter. Scoring is linear in deviation: 0 off = 100 points, dropping to 0 at 6 or more off (formula: 100 − 15 × |error|). Five rounds escalate in tempo and length — round 1 is a calm 60 BPM over 10 seconds, round 5 cranks to 150 BPM over 18 seconds with ±30% timing jitter, so even a brief glance away costs you several beats. Total cap is 500 and your best is saved in the browser. Tip: trying to track both the spike and the heart pulse splits your focus; lock onto one channel (the heart flash is easiest), count out loud — only switch to the ECG in the final round to lean on its sharper amplitude when the rhythm jitters.