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
Meet Bards in the Library
Rebuild all links in the game
Finish the game (or not?)
Meet a Serf in the Abbey
See the Great Door of the Abbey open
Visit the revived Abbey Garden
Validate all glyphs in the game
Activate all Terminals
Take a trip in the Alchemists' cable car
Attend the Bards' show in the Fortress
Leave the Armory with the wrong disguise once the Call is made
Rebuild half of the links
Reach Exile
Rebuild a first link
Reach the Galleries
Validate half of the game's glyphs
Winning at both games in the Gardens
Reach the Garden
Reach the Frontier
Discover the Preacher's corpse
Reach the Abbey
Ring the Abbey bell three times
Fill in the Journal's first page