Here is the full list of all 26 Pixel Puzzles: Japan achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
All Puzzles Complete!
Tsukubai
Enlightenment Attained
Himeji Castle Gatehouse
Gardens of Nijo Palace
Akai Hashi
Butsudan
Consciousness Raised
Hiroshima Castle Gatehouse
Temple Lanterns
Stop The Pop... With A FIsh
Cherry Blossom Over Water
Koen
Nara Temple Gates
A Mind In Training
Iwakuni Bridge
Komainu No Enryakuji
Osaka Castle
Red Temple Of Nara
On The Road To Enlightenment
Himeji Castle
Urabandai Lakes
Pull It OUT!
Torii
Komainu No Osaka
Zen Garden