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