Problem is, Gamestop's ToS is basically 'If the product is a failure, we will take it and give you a new copy' or so said my reciept when I got SR3, so I'd imagine it's a general company policy.
Store policies can be pretty flexible, depending on the person you end up dealing with and how you approach them (if you're frothing at the mouth and making threats you probably won't get very far, while if you're polite and coming at it with the attitude that you regard the person as being on your side and are trying to find a resolution that works for everyone then you'll have much better luck). Dealing with people face to face also makes them much more likely to want to be helpful as opposed to dealing with them through e-mail or phone (it's much easier to de-personalize people over these mediums as opposed to dealing with someone in person). There's always the possibility that you'll end up dealing with some inflexible [censored], but you won't know until you try. On top of that, if you don't get a refund from the store and end up disputing the charge, then the CC company has their own policies and they really couldn't give a toss about Gamestop's policies. Basically pursuing a refund through these routes doesn't take much effort and there's nothing to lose, so there's really no reason not to give it a try. After all, if you don't try then you
definitely won't be getting a refund.
But your EULA is with EA. Gamestop is just the retailer, if you have a problem with the product I'd take it up directly with the publisher.
What matters is who you have a business relationship with. In short, if you want your money back then you need to take it up with the company you handed your money to.