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.
Akai Hashi
Hiroshima Castle Gatehouse
Consciousness Raised
Butsudan
Temple Lanterns
Stop The Pop... With A FIsh
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
Komainu No Osaka
Zen Garden
Red Temple Of Nara
Pull It OUT!
All Puzzles Complete!
Enlightenment Attained
Gardens of Nijo Palace
Himeji Castle Gatehouse
Tsukubai