This project has been developing quietly in the background, but there's finally a new build available for free! You can try the first three worlds here:
https://www.newgrounds.com/portal/view/796886
This version has new content (a new world with new scenes), additions to old content, and some significant improvements to the core gameplay. I can't say exactly when the full game will be released, but we hope to move out of mechanic testing to production on the remainder of the worlds soon.