Experience

The player earns experience whenever enemies are killed. Different enemies are worth different amounts of experience (as listed on their individual pages). The amount of experience given by enemies is also modified depending on the difficulty level.

Whenever the player's experience passes certain predetermined thresholds, he gains a level. Whenever the player gains a level, he gets to select a new trait. Once the player reaches level 25, he will no longer gain additional levels, although level 25 is nearly impossible to reach in most game modes.