Hollow Depths is a self-initiated third-person puzzle survival game designed, documented, and developed independently in Unreal Engine 5. You play as a relic hunter navigating an ancient site, locating three hidden keys, following environmental clues, and evading patrolling sentinels with no combat available. Every decision matters with a countdown timer running. Built from a full Game Design Document through to a complete and polished build, featuring a quest system, foliage environment design, a fracture system, reusable interaction components, and a complete UI suite including HUD, menus, and game-over screen.