Metroland is definitely a family entertainment center. Generally this is just one business that may be indoors, outdoors or both. It can include go-carts, mini-golf, video games, batting cages, bumper boats and more. Disney Quest is definitely a family entertainment center.
A R/D/E Retail Dining and Entertainment complex is something more akin to a shopping mall with an entertainment edge. Newport on the Levy in Cincinatti, CityWalk, Downtown Disney, Sony Metreon in San Francisco are all considered RDE’s. These have more than one business, are generally the size of a shopping mall of sorts. Instead of a 90%-10% retail / dining to entertainment balance it’s more 50% – 50%.