Stygian: Reign of the Old Ones is a role-playing game that immerses players in a hand-drawn 2D world inspired by H.P. Lovecraft's themes of cosmic horror. Set in a doomed Arkham, players create characters based on 1920s archetypes and navigate a mysterious environment filled with abominations and challenges. The game features a unique spell system that can have dire consequences, alongside a strategic turn-based combat system reminiscent of classic RPGs. Players must manage their character's sanity, which influences dialogue options and gameplay outcomes.

With eight main character archetypes, each possessing distinct backstories and specialties, Stygian offers a rich role-playing experience. Players can recruit various companions, each with their own peculiarities, to accompany them on their journey. The Belief System adds depth to character interactions and sanity management, further enhancing the gameplay. In this world where madness reigns, players are encouraged to pursue personal goals amidst a backdrop of inevitable doom.