ME2 is pretty good, and you can refund games on Origin now.
Well, it should be noted how the "Great Game Guarantee" works:
Full game digital downloads (PC/Mac) published by “Electronic Arts” (collectively Electronic Arts Inc. if you reside in the United States, Canada or Japan and EA Swiss Sarl if you reside in any other country) and purchased on the Origin Store (Origin.com and purchases within the Origin gaming application) may be eligible for a refund if we receive your request within the earlier of: (i) seven (7) days from the date of purchase, (ii) seven (7) days from the game’s release date if you pre-ordered/pre-purchased or (iii) twenty-four (24) hours after the first time the game is launched or run. For full game digital downloads that are part of a bundle, the twenty-four (24) hour time period begins as soon as one game within the bundle is launched. Once a refund is issued, you will no longer have access to the game. To request a refund, visit your Order History and select the “Request a Refund” link next to any eligible product. Complete and submit the Refund Request Form. You will get a response within forty-eight (48) hours after your request is submitted and your refund within seven (7) to ten (10) days if you meet the Great Game Guarantee refund requirements.
It's designed to cater to people who experience unresolvable or otherwise annoying technical issues, not those who didn't do their research and later decide they don't like a game.