There are a bunch of reasons we use Flash for games<p>- we give a site a SWF and that's it, they have the game.  HTML5+CSS+JS+images+sounds+music+a flash bridge to handle audio, etc is a mess by comparison to "a swf".<p>- distribution is critical to the business of making Flash games, when you see a game on whateverwebsite.com that begins with the logo and branding of for instance www.armorgames.com, that's because Armor has paid the developer to brand that game with his site.  This alone is a massive industry that includes many amongst the most-trafficked sites on the met.<p>- power and functionality, every generation of the software Flash gets noticeably better.  Massive progress every other year, that allows developers to do things like use webcams for player movement, audio and visual sound effects, graphical work, only some of which right now is still years from being viable across the board in HTML5/CSS/JS.  New versions also enjoy rapid adoption rates by ocnsumers.<p>- truly cross platform, even if it sucks a bit on linux or whatever, we as developers don't have to do anything at all to accommodate anyone at all ... we write once and that's it.  The fantasty with html/css/js etc standards making this a reality for that platform have historically and currently not worked that well, the most obvious example being video codecs for html5, where you'll now have to sniff the user's browser and serve them alternate content.