I too bought the game and tried it on two systems and both times I couldn't trade in cards or if I could no one else could. Also I had the problem that if I could trade in cards I was able to do it a couple of times so instead of say trading in for 40 armies I was able to trade in again with the same three cards for 45 additional armies.Don't get me wrong risk is a classic that I always love, but it needs to work to be a classic.If you have the game and it doesn't have any bugs your lucky, I've returned mine and am trying out my second. I hope to keep the game if there is no bugs.