| ← → | Move your ship left and right. |
| Space | Fire. |
| Drag / tap | Move and shoot using touch. |
| Start | Begin the wave. |
Galaxy Defense is the arcade shooter in its purest form: a ship at the bottom, a grid of aliens descending from the top, and a single stream of fire between you and being overrun. Clear a wave and the next drops in lower and faster. It is the template a whole genre grew out of, and it still works because the pressure is honest.
Every wave is a small maths problem played at speed. There are more aliens than you can shoot before they land, so you cannot simply react. You have to thin them from the right places, keep your firing lane clear, and manage the rising tempo as their numbers fall and their speed climbs.
Shoot the aliens at the edges first. Clearing the outer columns widens the space you can retreat into and shrinks the block of targets from the sides. Punching a hole in the middle instead leaves two swarms still spanning the whole screen with nowhere for you to hide.
Keep moving unless you are lining up a shot. A stationary ship is an easy target for return fire, and the descending aliens speed up as their numbers drop. Small constant movement keeps you alive; committing to a fixed spot gets you hit.
Watch the pace change as a wave thins. The fewer aliens remain, the faster they move, so the last few are the most dangerous, not the easiest. Do not get careless just because the screen is nearly clear.
Do not waste shots. Your fire takes time to travel, and spamming it at empty space leaves you unable to hit the alien that actually threatens you. Aim each shot at a target that matters, especially any that has broken from the pack and is diving toward you.
Destroy every alien before they descend far enough to reach you. Then the next, faster wave begins.
The game ends. Keeping the swarm from landing is the whole objective.
Yes, both as a wave thins out and as you progress to later waves.
Yes, you can move and fire by touch as well as with the keyboard.
Nothing at all. The whole of Galaxy Defense is built into the page itself, which is why there is no loading bar and no waiting before you can play.