As a beta user of AdSense for Games, you can display video ads, image ads, or text ads within your online games to earn revenue. You'll be able to show these ads in placements you define, such as interstitial frames before a game, after a level change, or when a game is over. Members of AdWords team will sell your in-game ad placements directly to top brand advertisers, and you'll also see contextually targeted text and image ads based on content and demographic information. In addition, you'll be able to control the ads you see on your pages using our filtering options.
How would it benefit to an Adsense Publisher like me? Does one needs to be flash expert for that? Also, you said one can put the ads between two levels of a game...does this mean that the site has to have their own developed games?