Lantern Keep is a short portrait browser game made for Slapjam AI 2026's Castles theme. Shadows move down three stone lanes toward a moonlit keep. Tap the matching lane to send a lantern beam. Keep at least one heart until all 15 shadows have appeared to win.

Controls: Tap Left, Center, or Right. On a keyboard, use A/S/D or left/up/right arrows to fire; P or Esc pauses.

AI tools used: Codex assisted with game design, HTML, CSS, JavaScript, and browser QA. OpenAI built-in Image Gen created the visual concept, castle background, guardian sprite, shadow sprite, and cover art. No AI audio, 3D tool, sponsor tool, external font, or third-party asset pack was used. The game has no audio.

Created during the Slapjam AI build window on September 29, 2026. Solo entry by estona815.