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