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