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