Syringes are flying in and a boy has nowhere to hide but the platforms. Injection Invasion is a quick survival platformer: you move with the keyboard arrows or the mouse, jump and dash out from under incoming injections, and every second you stay alive adds to your score.
Levels get harder as you go, so instinct alone stops working after a while. Watch how the needles move for a moment before committing to a dash; reading the pattern first usually buys more time than reacting late. When you need a break from dodging, Classic Snake is a calmer kind of reflex game.