There is a easy way to unlock the achievement Illuminatus without having to grab each tinderbox.
Easy Way to Unlock the Achievement
There is a total of 151 tinderboxes in normal difficulty. To unlock this achievement the game only needs to notice the change between 150 and 151.
If you have a game saved on normal difficulty, go to the folder where it is. It's usually:
Open the saved game file with NotePad or WordPad and you will see a large text of code. Then you will need to find in the text the place where it says "TinderBoxesCollected" like this:
That "108" of the image is the total of tinderboxes found in my saved game. In your case it will be probably another value. The only thing left to do is replace that value with "150" and save the file. Then start the game normally and load the saved game. By grabbing just one tinderbox the achievement will be unlocked. That's all.
- If you don't have saved games, start a new game on normal difficulty and grab at least one tinderbox. If you don't take one, you will never find in the saved game file the value of the tinderboxes collected because it will never have been created.
- Make sure that the saved game is not the end of the game, because there will not be tinderboxes left to grab