You can put ads ... Those flash games are your content (make sure it is not against copyright and bla bla ) ... Google can index simple SWF files with texts ...
its highly allowed if you do not violate any TOS like adding copyright protected game, adult games etc..
You should probably make sure to include some regular text (not within the Flash file) on each page. Even though Google can index Flash files now, chances are the text from within a game is not going to be relevant to your site's content. Games tend to not use terms like "Flash games" or "arcade games" within the actual content of the game.
yes, adsense is allowed in flash games sites but i see lots of those sites are banned from adsense soon.
Do one thing ... use TOS supported games .. in the game page add some content which actually tells what is the game about .. if your site is dynamic, then a bit modification will help you out. Also put some feeds in all pages which will fetch data from other site showing latest game news .... This is good solve to this issue.
adsense on flashgames site is allowed but not on casino, gambling, pharmacy, adult contents and also sites containing copyright material
Since when was flash games any of the above. Yeah go ahead, plenty of people put them on Flash Arcade Websites.
Of course, simply because it's flash or a gamer website wouldn't disqualify it. Maybe checkout Google's help center for more information. https://www.google.com/adsense/support/