Here is the full list of all 25 Chants of Sennaar achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Reaching the real end of the game
See the captured monster in the Laboratories
Visit the revived Abbey Garden
Rebuild all links in the game
Finish the game (or not?)
Rebuild half of the links
Take a trip in the Alchemists' cable car
Validate all glyphs in the game
Activate all Terminals
Reach Exile
Meet Bards in the Library
Meet a Serf in the Abbey
Attend the Bards' show in the Fortress
Reach the Galleries
See the Great Door of the Abbey open
Validate half of the game's glyphs
Winning at both games in the Gardens
Rebuild a first link
Reach the Garden
Leave the Armory with the wrong disguise once the Call is made
Reach the Frontier
Reach the Abbey
Discover the Preacher's corpse
Ring the Abbey bell three times
Fill in the Journal's first page