Just thought since I have the opportunity I'd mention: My biggest problem with ImpactJS is that I'm required to pay before I'm allowed to try using it.

I've considered it a number of times but each time, that $99 barrier pushes me back towards the alternatives like Panda.js (which I believe is actually inspired by Impact). Not to mention Unity, which is free for some platforms.

If you offered a trial license, that would be awesome, although I understand you likely don't because of fear of abuse.