The plan to port Shiny Days to web has been scrapped since I don't want to interfere with the sales of any existing releases of these games.
I am still working on translating Cross Days, so the custom engine hasn't gone to waste. From what I've seen the Japanese version isn't available for purchase, is unstable, crashes frequently, and has no official English release, so it appears to be abandonware.
Of course, I will be consulting with JAST USA about this before releasing anything publicly. So you might even see an official translation for the game one day depending on how that goes!