Tentacle Thrive was the game that you look for?
Game link in new ground https://www.newgrounds.com/portal/view/718766
Here's link to the said game in this forum.
https://ulmf.org/threads/always-a-good-business-deal-v1-06-tentacles-thrive.10553/
There are alot of Ninja games out there. .
Could it be this one?
https://ulmf.org/threads/toraianguru-kuno-kunoichi-tsubaki-rj221304.11787/
Or this one
https://ulmf.org/threads/kunoichi-botan-enokippu.7529/
Here's how to unlock almost all things in game. I quoted from poster before.
Words of advice, you probably might want to read previous post before asking for something. Anyway have fun.
I dont know if Heroine Hunting count as one. but check it out.
https://ulmf.org/threads/mo2-ebisen-heroine-hunting.6968/
The Lewdbeasts, the Witch and her Daughter has pretty sad story though.
Maybe try like Violated Hero Series? (http://www.dlsite.com/ecchi-eng/work/=/product_id/RE087643.html)
It played like megaman alot, tile rpg battle. Mostly with monster girls and i guess the story and art also pretty decent.