I've been moonlighting as a Stencyl beta tester for a couple of months now, when time allows (I'm a busy guy). I just want to say a couple of things, hopefully without breaching the NDA in the process:
[*:3r5ojnd2]The programming system, strange though it looks, is probably the closest thing I've experienced to proper programming in a drag and drop system. [/*:m:3r5ojnd2]
[*:3r5ojnd2]The games they have demoed are not the only ones in existence, are they are still in development. There are many more in the beta community, including one of mine.[/*:m:3r5ojnd2]
[*:3r5ojnd2]The engine is Java based (pulpcore) and the games play in the browser, which means no hardware acceleration. It's a trade off of power vs. cross platform compatibility.[/*:m:3r5ojnd2]
[*:3r5ojnd2]The big selling point for Stencyl is the collaboration. There is a real emphasis on sharing resources and creating reusable assets, so that devs don't have to reinvent the wheel all the time.[/*:m:3r5ojnd2][/list:u:3r5ojnd2]
Overall, it's a decent game making system, and like all such systems it all depends on the talents of the people using it. There is enough flexibility in the software for someone talented to do some impressive work. I wouldn't necessarily say that it is competing with Construct - they have an entirely different set of objectives.