Get through the final credits of either DVD, both last episode and the DVD credits. The Japanese theme (from Tekkaman Blade) on the Main Menu will be replaced with the US Teknoman theme. This will also unlock another menu selection (seen as a Tekno Crystal around Blade, but hidden unless you move over to it). This unlocks an original, alternate "animated closing" using the US theme. Clicking the usual menus will reset everything. The Tekkaman Blade theme returns to Main Menu, and the hidden Tekno Crystal link no longer comes up unless you go through the final credits again. Both DVD's in Collection One have this unlockable hidden link.
All easter eggs were generously submitted by SirDonk