You think that web technologies are not appropriate for games?
Well, you are wrong.
There are a lot online games that are browser based. They use Flash/Shockwave or Java technologies. If the game is not graphic intensive, you can use simple HTML for output. There are many examples – from popular yahoo games, to miniclip and Swirve Utopia.
But, even graphic intensive games can be HTML based, actually DHTML. Take a look to: DHTML Lemmings