Walkthrough: Dungeon Defender, level 7 (Wizard/Hard)

Skill allocation: Three points into the manticore tree, everything else goes to the avatar.

Pause the game, and issue dig orders covering most of the treasure squares. Also, dig out the altars and temples as fast as possible.

Keep your avatar near the left spawning point, as seen on the screenshot. Start out with only a minotaur lair and your avatar on the left, and with an elemental and some minotaurs on the right.

Build the lairs as depicted below and focus on the demons (because the really hit hard) and the lairs around the bonus-providing squares (altars, temples).

Good luck!