There are two teams, the birds and the builders.
The builders can defend their fortress by building walls around their core. Builders can fly at the cost of moving slowly, they get a limited number of walls per person. Toggle builder mode by pressing B. You can push back the birds by pressing Q.
Birds will show up from both sides, tap the spacebar to fly, you are fast, and every time you hit a wall you will be bounced back, but the wall will take damage. You must hit the core on the side in order to damage it, your bird will be respawned once you successfully hit the core. You can change your direction of movement by pressing D.
If the time limit runs out, the builders win, if the birds successfully destroy your core, the birds win. The game will restart when either team wins.
The game is extremely buggy since it is using web-sockets and multiplayer, and if you have any problems use the Gamejolt version.
DISCLAIMER: Do not rate this entry based on the Gamejolt version of the game.