I did not share my opinion, so I will now:
Game devellop is a nice idea, but I find it inferior to C2, and here is why:
The html5 export seems more like an addition than a full export, just having pixelated graphics seems to be an absent option on it.
The IDE feels kind of disorganised, never found any real logic to it personnaly
I think they choose to support cocoonjs recently, not so much a bad thing if they can pull it off, but it is not encouraging
The event system is not as intuitive and readeable as C2's one (however, it is still far superior to clickteam fusion 2.5 from what I saw, but again clickteam fusion 2.5 event system is really outdated)
Little unease of use thingies adds up, I feel more like struggling against the IDE than using it.
However, due to its free price, his open source nature (even with a small community), and the fact it still works, and runs on linux, and html5 platforms (there is an html5 version of the IDE), it might still be considered a good choice.
The community on the other hand seems to not know a lot about html5, and think it is limited a lot (I remember reading that some people did not want an html5 app of game develop because they did not want to upload their assets anywhere, or did not want to be constantly connected to the internet for it to work, hello? We are in 2014, offline webapps that works with on disk ressources exists guys).