With all the grownups away on crusades, the little tykes left behind must defend Etheria's castle from teeming multitudes of monsters. Pick from four distinct heroes, then place structures like spiked blockades, fireball towers, and gas traps. Each youngster begins life as a wimp but grows into a formidable combatant thanks to customizable stats, unlockable abilities, and piles of shiny gear.

Play by yourself, and you'll grow weary of having to hoof it between distant chests for mana, performing all repairs and upgrades yourself, and enduring a frightening level of difficulty. Solitary play can seem more plodding and frustrating than enjoyable, especially as the strikingly detailed battlegrounds become ever more sprawling and labyrinthine.

However, Dungeon Defenders becomes an entirely different game the instant you join forces with up to three couch-bound or online allies. With housekeeping chores divided, you're all free to focus on ingenious structure placement and exhausting real-time combat. A Squire might place a blockade while an Apprentice erects a magic missile tower behind it. Meanwhile, a Monk could hold a group at bay and project an aura while a Huntress invisibly places a trap and then blasts the crowd from afar.

Even the sinister difficulty suddenly becomes a strength, as it guarantees you'll face all the evil you can handle even long after you hit the level cap. Once you've mastered the most expansive and demanding environments, you still have challenge modes to complete, epic equipment and animal companions to upgrade, and trophies to collect. As long as you're not dead-set on playing by yourself, don't miss one of the most exciting and habit-forming co-op experiences on Live Arcade.

On Xbox Live Arcade

+ Outstanding drop-in/drop-out co-op; sumptuous graphics; endlessly challenging.

+ Complementary array of defensive structures and heroic abilities.

- Solo play laden with timeconsuming chores; no host migration.

? Why doesn't Easy difficulty have any leaderboards?

9.0