When Stonefly promises a chill and tranquil adventure it's not telling the whole truth. Annika, a capable young pilot searching for her engineer father's stolen mech, finds herself under frequent attack from the bugs that protect the resources she so desperately needs. Much of Stonefly is spent propelling your insectoid mech through an arboreal maze, hopping from leaf to leaf and catching the breeze to higher layers of canopy. But the various minerals you must extract to craft mech upgrades are fiercely protected, and so the game's rhythm becomes one of sedate exploration punctuated by frantic skirmishes.

While Annika can modify her mech for combat, improving existing functions and installing new ones, the pattern remains the same throughout. While airborne, she can shoot at enemies directly below her; damage them sufficiently--basic enemies take only one hit while the toughest will require multiple strafings--and they flip over onto their backs. Once vulnerable, enemies can be blown off the edge of whatever leaf or branch constitutes the current battlefield, and thus eliminated.