We just added the Reaction Time Test. Press Start and the screen goes dark while you wait — the instant it turns green, click as fast as you can to record that round’s reaction time in milliseconds.
Across 5 rounds, your average and best update live after every round, along with a grade — Elite, Fast, Average, or Slow. Click too early and you’ll see a “too soon” message — that round won’t count, and you can retry it.
When you finish, you’ll also see consistency (standard deviation, showing how steady your rounds were) and your all-time best, saved right in this browser. Your per-round times are plotted as a bar chart so you can see your fastest round at a glance, and the game area keeps a fixed size across every state so the page never jumps around under you.
A bright red full-screen flash can strain your eyes, so the waiting state uses a dark color and only the click signal uses an easier-on-the-eyes green.