In levels 1 (Sol) and 4 (Deneb), destroy a particular obstacle to reveal warp links to levels 4 and 7 respectively, bypassing levels 2 and 3 and/or 5 and 6. Of course by skipping levels 3 and/or 6, you'll also miss out on the fuelbays in those levels to repair your vehicle and replenish your invisi cloaks.
