Thanks for the honest feedback.
The camera jerking as you fall far, I know what the issue is there, just need to implement a fix for it sometime. We have a couple of other bugs but not game breakers so left them for now.
As for performance it's using a few effects on the foreground and background layers so that might be the reason. We did test on a slower pc and had similar issues as you describe. We're just thinking about what to do with it next :)
There is a video on vimeo if you want to see it running at the proper framerate here:vimeo.com/56841843