Space Invaders

Space Invaders is a browser version of the arcade shooter that helped define the genre. You move a laser cannon across the bottom of the screen and fire upward at rows of aliens as they creep lower. The pace tightens as enemies disappear, leaving the remaining invaders moving faster and hitting harder. Destructible shields give you a little cover, but not for long, so every shot and every step matters. It still works for the same reason it always did: simple rules, rising pressure, and that stubborn urge to beat your last score.