I am almost for certain, it is a straight forward 100% for this game. It just takes time, not a real complicated achievement list.
There are like 6 achievements for the main quest-line, and the rest are simply tied to reaching a certain rank in all the "factions" (Mage/Fighter/Arena etc. etc.). Also, The Shivering Isles is pretty straight forward (And, IMO, exceptionally fun).
Originally Posted by suspect121
And, you are welcome. Enjoy the game.