Is there a way to skip the level before the final bossfight?

Solution 1:

There was a way, but Croteam fixed that bug: Guardian of Time in 5 min

Some players can still skip half the map when you fight Technopolips (in the area at 2:30 in video), by luring the sandworm to the wrong position where it can't kill you, but I think it is too hard and best just to use that time to try again.