Hollow Knight is a hand-drawn 2D action-adventure game set in the ruined insect kingdom of Hallownest. You explore interconnected caverns, ancient cities, and dangerous wastes, battling hostile creatures, uncovering secrets, and gaining new abilities that open up previously inaccessible routes. The game is known for its tight combat, atmospheric world design, and large amount of optional content, with all major post-launch expansions released for free.