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