Video game review Formulas, over time, tend to become formulaic. That’s not the case with “Lego Batman: Legacy of the Dark Knight,” the fourth entry in the “Lego Batman” series that began in 2008. The formula is familiar: a licensed property set in a world built out of Legos. But instead of just repeating what’s worked in the past, “Legacy” confidently builds on its tested formula, creating something familiar and fresh — and so very fun. Developed by TT Games and published by Warner Bros. Games, “Legacy” tells an original story of how Bruce Wayne becomes the superhero known as Batman and about his efforts to save Gotham from nefarious ne’er-do-wells. The story campaign, which lasts about 15 hours, dives deep into the Caped Crusader’s mythos, remixing and melding other Batman tales — So. Many. References. — to form one entertaining, if slightly disjointed, narrative. Functionally, the game comprises two main parts: the story and the open world.…