Blind Keys — free browser game

In the middle of the screen you see a horizontal bar with a fixed green target zone on it; a yellow indicator moves continuously back and forth along this bar, and your job is to press the Space key (or tap the screen on mobile) exactly while it's inside that green zone. Correct timing earns you +1 point; if you press outside the target you lose one of your three lives, and when your lives run out the game ends. It's a single-key, reflex- and timing-focused arcade game — easy to control, but hard to score consistently high. Every 5 successful hits, the yellow indicator's speed increases noticeably; that's why at later levels the time it spends crossing your target window is only milliseconds and you're pushed to the limits of your hand-eye coordination. Strategy: fix your eyes not on the indicator but on the edge of the target zone and track the indicator's approach with your peripheral vision; this improves your reflex response by 60-80 milliseconds on average, because central vision is slow to react. Another technique is called rhythm counting: count the indicator's full lap to yourself as 'one-two-one-two' and press on the target beat — the brain learns this pattern very quickly. At high levels, when the indicator gets very fast, switch to the 'predictive shot' method: press slightly before it reaches the target zone, because the lag from key to screen already adds a few frames of extra delay. Your best score is saved in the browser; a typical player stalls at 15-25 hits, an experienced player at 50+.