I just wanted to say that rarely are you ever allowed to return opened software. The only time I was able to do something close to return software was when I returned the first season of Lost at Target because the actual DVD was deformed when printed.
If anyone is intending to do this I am assuming game retailers are already prepared to reject your return. You might have some luck with the larger department stores (walmart or target) but generally speaking I think everyone should hold on to their copy for the time being. The price isn't gonig to go down for some time and you won't expect a compilation game of the year edition till later next year.

And read the forums. New post today details new info.

You can return anything you want if you complain about it long enough, usually. If unsuccessful, go to another location. I returned a two-year-old PS2 (at the time) that I unsuccessfully modded like 8 years ago even though the serial model didn't match to a Target. Even though they have a poster on their wall specifically for game devices saying not to return them. I returned a launch PS3 that was opened and used because I felt guilty about buying it (only to buy a non-BC model a year later) and just told the manager it was open when I bought it (which it actually was, although clearly unused at the time). I bought a copy of a game once that had the Antz DVD movie in it and the manual removed. You can tape up the shrink wrap carefully and go that route although it's sure to make a gamer (like myself) mad. Non-shady / illegal methods aside, just try taking it back. They might take it, they might not and no point in feeling bad especially if it's a place like walmart. They can eat the loss. Wouldn't want to take this wonderful game back though, even with the bugs