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