I just bought Arcania, and tried playing it on my HDTV. First thing I noticed, was the framerate, which was horrible. and then the text, which was unreadable. 
 I tried all the evening to check if I could do something, and no, the game is quite unplayable that way. 
Thing is, technically, It is in working order... 
Should I bring it back to ebgames, asking for a refund on what I consider unplayable, or would it not be accepted as the product is currently in a "working condition"?.

I don't think this has anything to do with ethics, really. I think take it back, and if they don't accept it as a return, at least do a trade-in and get some store credit so it's not a total loss.

Takerback.
At least get something you'll enjoy playing.

sad thing is, it doesn't seem that bad a game. thank you for your answers, I'll bring it back tomorrow. :)

lol well it was a first, since my PC recently broke, and I really wanted to play Arcania :D

This is inconsequential. Do what you want to do.