In my opinion, game traffic is very very hard to convert due to its traffic demographic. Although lately study shows the average gamer is actually 31 years old yet I believe most of the mature gamers are playing super sophisticated games.
What I am trying to say is sophisticated gamers are also internet-savvy, they do not fall into ads often. Hence the traffic is very hard to convert.
Personally I still prefer going for movie or e-book traffic. Demographic is more naive and the ROI is always positive. I still know a network that runs game offer. PM me if you want to learn about it.