The 3DS started this revolution for Nintendo, and now the Wii U is continuing it: in addition to smaller downloadable games, the Wii U is capable of downloading full retail experiences directly from the eShop.

So if you suddenly get the urge to play ZombiU  but your local store is sold out of it, you can simply buy it online and install it directly to the console. Just be careful not to run out of spaceā€”it's probably best to spend the extra $50 on the deluxe console with more storage.