Dungeon Defenders

As the achievement description says, simply complete all levels (including the Bonus level) on any difficulty. As one may be able to guess, completing on Easy is the best, quickest and easiest way to do this. Some possible tips:

- Create a character of each class and see which you like the most. Then play with that character (you're gonna need to beat the game, or the last level at least, to get every achievement, so you might as well level them up a bit).

- Use your mana to upgrade your weapons, armor and pets. Some suck, but upon increasing the stats, become quite useful (elemental damage increases faster, but if the enemy is immune, they'll take very little damage).

- Play as a group, while more people equals more monsters, this also allows you to relax a bit, as a combination of characters equals great defense.

- Easiest way (IMO) is to use the Squire who has incredibly high Tower health and attack, this'll make some towers untouchable (ie the Bowling Ball, Javelin tower and Slicer Blockade).

Simply complete each of the 13 missions (Yes, this includes the bonus level Glitterhelm Caverns) on any difficulty setting as the achievement states. When you look at the Eternia Crystal in the Adventurers Tavern and press Y on it, you can scroll through your statistics for each level. Here it will show a ribbon for each level on each difficulty so you know which levels you still need to complete.