Putting portals and other Portal mechanics into a bridge builder is a great idea even if the bridge building itself is pretty basic. Each level is really long and requires you route the car (or an absurdly long convoy for extra credit) through portals and around obstacles, which is real novel, though it does become a bit too much work pretty quickly. There's also some trademark Portal humor which isn't particularly sharp, but does remind you of the original games and the jokes they told.