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