The Final Level

The Final Level is the final stage of the main campaign of VVVVVV. It can only be accessed after rescuing all 5 crewmates.

Story
Immediately after saving the fifth crewmate (Victoria, Vermilion, Verdigris or Vitellary), they are seen safely making it to the ship, albeit without the player. Violet asks where Captain Viridian is, and the rest of the crew become worried.

The scene then switches to Viridian, who finds themself alone in a new polar dimension area. They continue through more obstacles until reaching the dimensional stability generator, which they infer to be the source of the dimension's interference that caused the ship to crash. However, on disabling the dimensional stability generator, the dimension begins destabilising. Viridian runs through the final stretch of the level, finally ending up falling endlessly in outer space.

With the interference gone, at this point the crew is able to locate Viridian and teleport them back on board. The crew explains that while they can explore for a little while, they can't stay in Dimension VVVVVV much longer due to its impending collapse, and are ready to leave for home. Captain Viridian resolves to stay in the dimension for a little while longer, so that they can find a way to save both their home dimension and Dimension VVVVVV.

Trinket locations
Only one trinket is present within The Final Level, at the end of the level before the player flips and enters outer space. Assuming no glitches, this is the only mandatory trinket in the game, since there is no alternate route that bypasses the trinket.