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