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