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