Ilo and Milo are the best of friends, but somehow they always get separated. These antenna-sporting dudes look more like stubby-limbed plush toys than adventurers, but they’ll go to extraordinary lengths to be together again in this cute-as-a-button puzzler. Your job seems easy at first: bring about a reunion on each stage while switching between characters as often as you like.

Unfortunately for Ilo and Milo, what at first glance looks like an invitingly cuddly world of toy blocks is actually a fiendish gravity-defying labyrinth. Paths twist like licorice spirals, red carpets turn walls into floors, and fragments of your lost memories litter every inch. Tutorials introduce you to the basics in baby steps (e.g., you can pick up and move only one block at a time), but watch out: ilomilo will test your capacity for spatial reasoning like it wants to snap it in two.

You’re not alone on this journey, either. Though there’s never any threat of death, you’ll run into the likes of obstructionist pop-up blocks, four-legged herbivores, and troublemaking sock puppets. Getting around these creeps — or figuring out how to turn them into unwitting allies — demands teamwork. Often you’ll need to maneuver Ilo and Milo close enough for them to trade the special blocks that bridge gaps, rise upward, open trapdoors to the flip side of your current platform, and more.

Frankly, figuring out how to arrange these topsy-turvy tête-à-têtes will twist your noodle till it hurts. Casual gamers may find that the balance tips over into frustration too frequently, but true puzzle hounds will adore the satisfaction that comes from conquering such elaborate playgrounds. Fans will certainly get their money’s worth, too. Merely completing each stage is one thing; gathering every collectible photo, vinyl record, and “Safkas” (tiny stranded critters that you rescue from remote corners) is quite another.

Sadly, offline co-op always leaves one player with nothing to do but buzz around the screen or stage cutesy drum-beating demonstrations to demand a turn at the helm. But with almost 50 cranium-splitting puzzles to solve, loads of collectibles to scavenge, and step-counting efficiency leaderboards to climb, ilomilo is still an outstanding meal for one.

On Xbox Live Arcade

+ Four chapters of challenging puzzles in charming worlds.

+ Amusing array of special blocks and troublemakers to gather and master.

- Local-only co-op’s ill-conceived turn-taking.

? Why doesn’t progress carry over from solo- to multiplayer, or vice versa?

8.0