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