I just had a quick look and several things stand out. The side ad on the home page isn't fully visible, the page is wider than the browser, not everyone has (or uses) widescreen windows, plus the game graphics are way too small imho, it's hard to tell what any of the games are. It's a bit 'busy' for my liking, sorry.
The main thing though is the ads on your game playing pages, you're putting your site/account at risk with them being so close to the flash game. See this for clarification, google's own words: Avoiding accidental clicks Pt. 1: Keeping the right distance - Inside AdSense. I know games sites are harder to monetize but if you lose adsense on it it's not worth doing. You need a lot of traffic to make them pay.