Mega Man Zero Collection is a compilation of four Mega Man Zero games originally made for the Game Boy Advance plus something new.
That “something” hasn’t been announced by Capcom yet. The trailer name drops the feature, though, and says Mega Man Zero Collection is the ultimate collection with two exclamation points.
Did you notice the art on the bottom DS screen? There are menus and numbered pictures too. Maybe Mega Man Zero Collection has a built in art gallery as a bonus too.