Unity 3D, the increasingly popular WYSIWYG—ish engine for building video games, does a lot of things really well. Helping you build in-game user interfaces? That's not one of them. At least, not ...

That screen up there is what greets players when they start Unity, developer Ubisoft’s 2014 installment of the popular Assassin’s Creed franchise for PlayStation 4, Xbox One, and PC.