The player is a presence — an intelligence without a body — that moves across 650 three-dimensional landscapes exclusively by teleportation, transferring between robot hulls distributed through the terrain. Any object within the line of sight can be absorbed for energy, as long as the square of landscape beneath it is also visible. Energy creates new robot hulls, trees to block lines of sight, or boulders to stack for elevation. The objective on each landscape: reach higher than the Sentinel and absorb him before he absorbs you. The Sentinel rotates steadily, consuming everything in his field of vision more substantial than a tree. Later levels add sentries threatening from multiple directions simultaneously.