Apparently it isn't all of them.
Source: http://nintendoeverything.com/123269/nintendo-shares-more-details-on-e3-program-with-best-buy/NintendoEverything said:...
Games will be playable at 110 Best Buy locations. They’ll be playable between 4 PM and 8 PM local time on June 12 and between 1 PM and 5 PM local time on June 15.
The full lineup of participating US Best Buy outlets can be found below. Follow this link for the most up-to-date list.
Alabama
Birmingham
Huntsville
Arkansas
Fort Smith
North Little Rock
Arizona
Phoenix
California
Culver City
Elk Grove
Emeryville
San Jose
Tracy
Visalia
Colorado
Denver
Connecticut
Manchester
Delaware
Wilmington
Florida
Brandon
Fort Myers
Gainesville
Kissimmee
Miami
Pensacola
Georgia
Augusta
Duluth
Savannah
Smyrna
Iowa
Cedar Rapids
West Des Moines
Illinois
Bloomington
Schaumburg
Indiana
Greenwood
Kansas
Overland Park
Wichita
Kentucky
Florence
Lexington
Louisville
Louisiana
Harvey
Massachusetts
Cambridge
Dedham
Worcester
Maryland
Frederick
Glen Burnie
Wheaton
Michigan
Ann Arbor
Flint
Grand Rapids
Rochester Hills
Minnesota
Eden Prairie
Missouri
St. Louis
North Carolina
Cary
Fayetteville
Pineville
Winston-Salem
New Jersey
Iselin
West Paterson
Woodbury
New York
Albany
Amherst
Long Island City
Syracuse
Valley Stream
West Nyack
Ohio
Fairborn
North Olmsted
Reynoldsburg
Toledo
Oklahoma
Oklahoma City
Oregon
Portland
Pennsylvania
Erie
King of Prussia
Pittsburgh
Reading
Whitehall
South Carolina
Greenville
North Charleston
Tennessee
Brentwood
Knoxville
Memphis
Texas
Arlington
Austin
Houston
McAllen
The Woodlands
Tyler
Utah
Sandy
Virginia
Charlottesville
Glen Allen
Virginia Beach
Vermont
Williston
Washington
Lynnwood
Wisconsin
Greenfield
jmoe316 said:Come play some of our new E3 2013 Wii U games at Best Buy locations across Canada!
Demos will be at Best Buy Canada locations in:
Ontario: North York, Toronto, Mississauga, Windsor, London, Ottawa, Kingston, Brampton, Oakville
Quebec: Montreal, Lasalle
Manitoba: Winnipeg
Saskatchewan: Saskatoon
Alberta: Edmonton, Calgary (2 locations)
British Columbia: Vancouver, Langley, Richmond
Nova Scotia: Dartmouth
Check back closer to E3 2013 to learn what games will be featured!