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