Defend Earth — 60-Second 3D Alien Shooting Aim Trainer

Defend Earth is a free 60-second 3D aim-training game built with three.js, set in an Earth-orbit view of a physically simulated solar system where every planet orbits and rotates at its own scaled speed. Alien invaders (🤖👾👽🛸) spawn 24–46 units away and drift sideways at a speed that ramps from 0.05 to 0.25 rad/s over the round; holding your crosshair on one for about 130 milliseconds locks on and fires automatically. Hits landed within 1.2 seconds of each other chain into a rising combo streak.

Yes, completely free — no download, no registration, no payment and no ads. Just open the page in a WebGL-capable browser and a 60-second round can start within seconds.

No manual clicking is required. The game uses lock-on auto-fire: keep the center crosshair over a target for roughly 130 milliseconds and the shot fires itself, so the skill being measured is purely how fast and precisely you can move your crosshair onto a moving target.

On phones the game reads the device gyroscope — tilting up to about 30° sweeps the crosshair across the full view range, roughly ±149° horizontally and ±57° vertically. iOS prompts for motion-sensor permission the moment you tap Start, since that request has to happen inside a real user tap. If sensors are unavailable or permission is denied, the game automatically falls back to touch-drag aiming with momentum instead.

Short, focused 60-second sessions of crosshair-placement practice are a common warm-up drill for FPS players, and the round length is deliberately short enough to repeat many times in a row. Defend Earth specifically trains smooth tracking and quick target reacquisition — every hit inside the 1.2-second combo window raises your streak, rewarding consistent follow-up shots rather than one lucky flick.

Any modern browser with WebGL support — Chrome, Edge, Firefox or Safari — on desktop or mobile, since the entire solar system, starfield and target physics run client-side with three.js and no server round-trips during play. If WebGL is unavailable, the game shows a compatibility notice instead of a blank screen.

Your score for a round is simply the total number of alien targets you lock onto and destroy within the 60-second timer, with hit streaks inside the 1.2-second combo window shown as a rising combo counter. When a round beats your personal best, a submit button lets you post your score with a nickname to the global leaderboard to compare against players worldwide.