How to Play DefOrbit — Free Browser Space Shooter, No Download

What is DefOrbit?

DefOrbit: Earth Defender is a free browser space shooter where you pilot a ship orbiting Earth and defend it from endless waves of alien invaders. Play instantly in any modern browser — no download, no install, no account required. Your ship continuously orbits Earth and fires automatically; you aim by moving your mouse to intercept incoming enemies before they breach Earth's shield.

The game features six weapons with four evolution tiers each, five unique boss encounters, four difficulty settings, and 2-player online co-op. Scores are submitted to a global leaderboard, making every run a competition.

Controls

DefOrbit auto-fires — there is no fire button. Your ship continuously orbits Earth and shoots automatically. You only steer, drop bombs, and switch weapons.

On mobile, move your finger to aim — firing is automatic. A dedicated bomb button appears on the HUD.

Scoring and Combos

Every enemy kill earns points. Chaining kills quickly builds a combo multiplier shown in the top-left of the HUD. The multiplier increases as you keep up a rapid kill pace — let the combo bar drain and it resets to ×1. Boss kills award large point bonuses, with harder bosses giving more.

At the end of each wave you are scored on kills, accuracy, and Earth's remaining health. Keeping Earth's shield high and clearing waves quickly are the fastest paths to top-leaderboard scores.

Difficulty Modes

Weapons and Upgrades

You start with three unlocked weapons — Pulse Cannon, Scatter Shot, and Plasma Lance. Three more unlock through in-game milestones: Homing Darts (500 total kills), Plasma Burst (reach Wave 20), and Ricochet Bolts (defeat all five boss types).

Weapons evolve through four tiers (I → II → III → MAX) by collecting the matching weapon drop mid-wave. Each tier improves fire rate, damage, or projectile count. You carry a primary and secondary weapon simultaneously and swap with Q. Read the full breakdown on the Weapons page.

Boss Encounters

Every few waves a boss appears: The Phantom, The Serpent, The Crystalline, The Guardian, or The Swarm Mother. Each has distinct mechanics — teleportation, segmented bodies, splitting on death, rotating shields, or minion spawning. Bosses enter a faster, more aggressive second phase at half health. Defeating bosses unlocks weapon milestones and earns the largest point bonuses in the game. See full strategies on the Bosses page.

Co-op Mode

DefOrbit supports 2-player online co-op via WebSocket. Select CO-OP MODE from the main menu and choose Host. You will receive a room code and an invite link — share either with a friend. The joining player enters the code or follows the link, and both pilots defend Earth together in real time. Co-op is available in both Classic and Endless modes.

Frequently Asked Questions