Tentacular Industries software
Tentacularity is a hentai puzzle game where you guide tentacles to girls. It runs on Windows, x86/amd64 Linux, and MacOS 10.4+. You can buy it through BMT Micro: Windows version, Mac version, Linux version.
Yuri no Yume is angsty, mysterious lesbian hentai romance as an episodic kinetic novel (if you aren't familiar with kinetic novels, they're sort of midway between anime and manga.)
The first chapter is free; runs on Windows, x86 Linux, and MacOS 10.4+.

You can buy episode 2 from CR3; I'll add other vendors if requested.
You can buy episode 1 from:
CR3 (All versions, downloadable, Visa and MasterCard only)
BMT Micro (windows / mac, linux; accepts Visa, MasterCard, Eurocard, Amex, Discover, Diner's Club, JCB, Switch, Solo, Maestro, PayPal, Deutsche Bank, mailed cheque, in £/€/US$)
Lulu (All versions on CD)
There's also a mosaic-censored version for distribution in Japan, available through DLSite and DLSite Japan. DLSite Japan accepts several additional payment mechanisms; both branches of DLsite only distribute the Windows version.

The first chapter is a free download.
Torrent download: windows, mac, linux
Web download: windows, mac, linux.
Catgirl Training is a fun hentai kinetic novel starring the Professor and his cat-slave, Oneko-chan. Adults only, contains light BDSM. Free demo, runs on Windows, x86 Linux, and MacOS 10.4+. You can buy Catgirl Training from:
CR3 (All OSes, downloadable),
DLSite Japan, or DLSite US. Both branches of DLSite sell a mosaic-censored version (to comply with Japanese law); CR3's version is uncensored.

There's a free demo of Catgirl Training:
Torrent download: windows, mac, x86 linux
Web download: windows, mac, x86 linux

Affiliate software

(I didn't write these, but I get a commission on them if you buy through these links - and I did help test them.)
In Fatal Hearts, Hanako's newest game, you play the role of Christina Robinson and help her to unravel the mysterious forces behind her dreams - and the all too real mystery of a murderer who strikes without warning. Fatal Hearts is is an interactive visual novel with lots of puzzles; it runs on Windows 2000 or later. Buy through BMT Micro or download free trial.
Cute Knight Deluxe is an improved version of Hanako's award-winning Cute Knight, featuring enhanced graphics, new plot twists, an improved Wizard's challenge, and new items. Gameplay is rather similar to the popular Princess Maker series. Buy through BMT Micro or Download Free Trial.

(If you want the original, it's also available - Buy | Demo )