This is the final cutscene of Jak and Daxter: The Precursor Legacy.

It is an ancient Precursor door that will only open if you have collected at least 100 Power Cells.

When you have 100 Power Cells, the door opens and there is a bright light shining out of it.

You get teased because everybody says things like: "Wow! It's beautiful!" But actually there is nothing to see. The game takes you back to the main menu leaving you to wonder. It is an interesting note that if you have 100 Power Cells prior to defeating Gol and Maia then the cutscene is combined with the ending scene in Jak and Daxter: The Precursor Legacy. Keira will mention that they need 100 power cells to open the gate and Daxter responds with "it just so happens we have 100 power cells"

This turns out to be the Rift Gate and Rift Rider in the beginning of Jak II.