It's interesting that rather than building a micro-library they've chosen to use a compile time instead. I guess I'd prefer to see this integrated into my usual JS libraries (YUI, jQuery).
That said it's pretty interesting. Even if some of the syntax is slightly jarring.
Neil Mix implements similar transformations in Javascript in Narrative JS: http://www.neilmix.com/narrativejs/doc/. However, as I recall it aims more to provide some of the main benefits of continuations rather than a complete implementation of continuations on top of Javascript, which is more where I was trying to go with jwacs.
Jwacs introduces very little new syntax to Javascript; I'm curious to hear which bits you find jarring, and what you would have preferred to see.
But, it extends the syntax of JS, so the only thing one can do, is to create a compiler for it to compile into JS that is compatible with the target interpreter (most likely a web browser).
In this case, I believe he outputs the "compiled" (more appropriately maybe, "transformed") code in Continuation Passing Style[1] where appropriate.
That said it's pretty interesting. Even if some of the syntax is slightly jarring.