Well then get a refund I guess ? I really dont know you and can only base my statements on what you are saying. And, logically, it concludes from your statements that you should get the refund and get the game again later, whenever you have a faster computer.
Personally I'm not bothered. Sure the game has lag right now. More than just 30 fps for me, which for the record is still very, very fast. I doubt I can even see the difference between 30 and 60 fps.
But because the game is turn based, I can play it. I could play it even with 5 fps or even 1 fps or even less.
