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.
Enlightenment Attained
Gardens of Nijo Palace
Himeji Castle Gatehouse
Akai Hashi
Hiroshima Castle Gatehouse
Consciousness Raised
Butsudan
Temple Lanterns
Cherry Blossom Over Water
Koen
Nara Temple Gates
A Mind In Training
Iwakuni Bridge
Komainu No Enryakuji
Osaka Castle
Torii
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
All Puzzles Complete!
Tsukubai