Ok, here is is the list of games that i've downloaded for free so they work for sure.

ME1, ME2, BF2142, Shift 2, MoH, Dragon Age Origins, Dragon Age 2, FIFA 12.

The best way to do this is to add all of them to your cart at once, apply code, and check out. If you have already got some games and going in for more then logout, clear origin cookies, open the website (don't log in), pick the gaames, add them to the visitor shopping card, apply code, and then log in.