Personally I recommend Google AdWords for marketing online. I'm not involved with any game sites myself, but I am sure that Google AdWords, if you take the time to learn how to do it right, could be hugely successful for you. Don't rush into it though!
Yes, with AdWords you will be able to target a specific audience. People clicking on your link will have done a search on a gaming topic of some sort. It's a great way to get the word out to the people you WANT to reach!