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