Before taking your rocket out into space, learn to control it in the obstacle course which is Gravity Thruster. You'll be flying in a gravitational field, so you have to thrust with one hand and steer with the other. Learn to use the tractor beam to carry orbs along with you, so you can move them to their goals to unlock the exit portal and fly out of each level.
Game Controls:
The in-game animated instructions will explain the controls.
Use the Mouse to Direct your craft, mouse button or E to Shoot.
Use Up Arrow, or W to activate your crafts thruster to propel it forwards.
Use Space, or Q to activate and deactivate the tractor beam.