hey Danny,
im not going to give a 'guesstimate' on the domain.
i dont have recent exp with games related sites
but I will give you a hint on how to run it.
use an application call 'AV Arcade'
therefore your using your domain to its full potential.
there is another i think it might be a wordpress plugin called 'MyArcadePlugin Pro'
use adf.ly to do your marketing as it could be a bit of help when people are doing 'intersital' redirects
adf.ly is cheap
I run in competition to adfly but if i list it here in a post, it would be classified as 'spam'
personally I think AV Arcade is better but I cannot explain the application in depth seeing it was a very long time ago that I used it
any guess on the value would simply be that 'a guess' that would be horribly wrong.
I dont know the CPC and audience, searches per GEO region etc etc
hopefully one of the more senior members has some experience in this field and can be of much better help.