Flash is for small games 2D and 3D, big games ? you can not handle efficiently not because the platform limitation but the toolchain is very poor. If anyone has ever use the Flash IDE, you know what I mean, crash quite a lot, very buggy and incomplete features. Flash IDE is for asset creation only.
Flash is multi-purpose platform, you can create apps, games or anything you can think of at client side, It's very easy to customize the interface, actionscript 3 is a good language, web target run pretty well (compable to other technogolies)... for other targets (AIR => Mobile, Desktop), the performance is not very great.
If you really look onto Flash on devices, you need to use frameworks like Starlings for GPU-accelerated stuffs (or implement your own ?)
If you are Indie mobile developer, I recommends Unity3D if you are going for 3D, HaxeNME or Corona (I don't like Lua, btw) for 2D ... much better performance and workflow and stop the headaches.
To say the truth, after more than 5+ years works on Flash platform (look at my username ), Adobe really loses all my trust : a buggy toolset, a bunch of incomplete features, crash all the time, cost a ton of RAM, put cost on everything they can ever think of (look for "tax on speed" on Google to know what I mean) ... very frustrating experience ...
Hopefully that it will help someone.
Edited by thienhafash, 02 March 2013 - 09:18 PM.