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