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