A very simple rotating turret for Spacejs.org

gistfile1.js

var turn = 20;

on('start', function(){
  ship.ready();
});

on('turn', function(){
  //Show current life
  utils.print('Life' + ship.life)
  //Turn by 20deg
  ship.turn(turn);
  //Fire the gun in direction of ship.angle after the turn.
  gun.turn(ship.angle + turn);
  gun.fire();
  ship.ready();
});