Here is the full list of all 21 External Visions achievements.
Get both "Item accumulator" and "Cooldown watch"
Unlock the locked door in area A6-2
Complete the art goods quest
Get the shield nullifier item
Get the dragon minion
Use each one of the one-use items
Make one skill upgrade to each power
Open 30 chests
Open all the skillorb chests
Find the hidden catacomb in the Library
Uncover the hidden door in the "Warehouse" level
Visit all the levels
Complete the flower quest
Forge the master key from the shards
Defeat "The BOSS"
Defeat "Zealot"
Defeat "The Evil Woman"
Defeat "The Geek"
Defeat the last boss
Beat the game
Beat the game in hard difficulty