Lots of online graphics-intensive games are requiring 11.3 or later, and 11.2 is where official development stopped. Google’s bought out a version of Chrome that will sort of work, but not for most games.
http://www.omgubuntu.co.uk/2012/02/adobe-adandons-flash-on-linux
http://en.wikipedia.org/wiki/Flash_for_Linux
http://www.engadget.com/2012/06/29/chrome-20-browser-released-64-bit-linux-flash/
Chrome is worth a try I guess.
On my old machine I had all the browsers, even Safari (very buggy on Win Vista)