A Real Human Benchmark Alternative
Human Benchmark gave a generation of players their first reaction time number. SERO picks up where it left off — same instant-stop principle, but with ten levels of escalating difficulty, a global leaderboard, a 14-day competitive season and a free Android version on Google Play. If you have already beaten Human Benchmark, SERO is the next step.
▶ Play SERO nowFree · No signup · Web + Android
What is different from Human Benchmark
Human Benchmark gives you five attempts and averages them. SERO runs ten different precision tests in a single 90-second session, so a single lucky tap cannot inflate your score. You also get a permanent profile, a country ranking and a fresh season every two weeks.
Why precision matters more than reaction
Raw reaction time hits a biological floor around 150 ms. Above that, the real skill is precision — stopping the timer exactly at 0.000 instead of 0.020. SERO rewards that precision with exponentially higher scores, so the leaderboard separates good players from elite ones in a way a single-click test cannot.
Free, web and mobile
SERO works in any modern browser without an install, and an Android app is available on Google Play for full-screen play with haptics. Everything that matters is free. Optional cosmetic skins exist but never affect scoring.
Common questions
Is SERO actually harder than Human Benchmark?
Yes. Hitting under 200 ms on Human Benchmark is easy; hitting a perfect 0.000 on SERO once in ten attempts puts you in the top few percent.
Does my Human Benchmark score translate?
Roughly: a 200 ms HB score usually lands around a SERO precision of 0.030–0.050 on the early levels.
Is it free forever?
Yes. The game and leaderboard are free. Only cosmetic items are paid.