https://www.dlsite.com/maniax/work/=/product_id/RJ288896.html

Main story: https://e-hentai.org/g/650518/46c1949325/
Omake: https://e-hentai.org/g/1769045/5f1e63e653/

This is indeed one of my favorite stories. I'm also expecting Haruki's final episode.

BTW, I finally rewrite my DLSite download script for this one, now I'm able to download those I could not in the past.
Please note that images are downloaded from the DLSite web viewer, thus the images have 1280px height and jpg format. I want to keep the quality during the puzzle game, thus the final result was png. This is bullshit, but I do not produce new bullshits during the process.
I probably won't share this script to prevent DLSite from banning this method. I'm also aware that someone can crack the dlst or cpd format to get higher-quality images. I'll not go that way until I can figure out how to write my own tools in the future.