Create twists worthy of a minotaur.

Fieldrunners follows the worn path of other tower-defense-style games, adding little new but matching those puzzles' addictive hook. Raiders try to blindly charge from a gate to an exit, and you only have an assortment of automated turrets to stop them. Each destroyed enemy earns cash to place fancier guns, and Fieldrunners strikes a good balance, giving just enough money to stay ahead of the waves of enemies.

The puzzle elements are revealed in the ways you trap the escalating numbers of foes. They'll run towards the exit in a straight line unless forced through mazes of your turrets, although you always have to leave some kind of path for them to eventually reach the goal. And a few types of air units--helicopters and blimps--require additional preparation, since they can just fly straight across the battlefield. We liked gradually unwinding these layers of strategy from simple rules.

While the graphic and sound production excels, Fieldrunners trips on the extras. A second map shuffles in enemies from two start and finish points, but we wanted even more creative obstacles and remixes. Without more variables, the premise grows repetitive, especially when waiting for slow-moving attackers; why not speed up the marching units if satisfied with your defenses?