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
Stop The Pop... With A FIsh
Cherry Blossom Over Water
Consciousness Raised
Butsudan
Temple Lanterns
Osaka Castle
Hiroshima Castle Gatehouse
Komainu No Enryakuji
A Mind In Training
Nara Temple Gates
Koen
Iwakuni Bridge
Torii
On The Road To Enlightenment
Urabandai Lakes
Himeji Castle
Pull It OUT!
Red Temple Of Nara
Komainu No Osaka
Zen Garden