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