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