For issues with extracting the zip file:
Download both files, then right click Trap_Genesis_0911i.zip.001 (aka part 1) and extract. It should work after that. We had to temporarily split the zip file into two parts.
Story-wise this is another direct sequel, albeit one that kinda goes off the rails. Yes, there is still an ongoing plot about the shrine and the various things involved, but the new face hijacks things to where things are somewhat random. Still the scenes are great and while there is still censorship it is toned down a bit so you can at least make out what is going on. Oddly while it is definitely a finale, there's a lot introduced.
All that said, as mentioned within another comment the zip files are split into two. However these files are unable to be extracted via native windows. A support case I opened recommended 7-zip which did work, but this odd difficultly with the files along with requiring an outside software surprised me. The game did work, but I don't know why I had to jump through hoops. Still good overall, but it had to be said.
Download both files, then right click Trap_Genesis_0911i.zip.001 (aka part 1) and extract. It should work after that. We had to temporarily split the zip file into two parts.