Here is the full list of all 21 Stay home and play with waifu! achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
You unlocked new Masaaki image in Gallery!
You unlocked new Kaiyo image in Gallery!
You unlocked new Hachiro image in Gallery!
You unlocked new Gina image in Gallery!
You unlocked new Cho image in Gallery!
You unlocked new Azumi image in Gallery!
You unlocked new Ami image in Gallery!