{"id":4171,"date":"2026-09-24T15:50:09","date_gmt":"2026-09-24T13:50:09","guid":{"rendered":"https:\/\/retroplaynow.eu\/arcade\/light-up\/"},"modified":"2026-09-24T15:50:11","modified_gmt":"2026-09-24T13:50:11","slug":"light-up","status":"publish","type":"rpp_game","link":"https:\/\/retroplaynow.eu\/it\/arcade\/light-up\/","title":{"rendered":"Light Up"},"content":{"rendered":"

Light Up, also known as Akari, is a puzzle of illumination and shadow. A grid contains black walls and white rooms. Your task is to place light bulbs in white cells such that every white cell is illuminated \u2014 either containing a bulb or being in the line of sight of one (horizontally or vertically, until blocked by a wall).<\/p>\n

Two constraints make the puzzle challenging. First, no two bulbs may illuminate each other \u2014 if two bulbs are in the same row or column with no wall between them, they conflict. Second, numbered black cells (0-4) indicate exactly how many bulbs must be placed in the four orthogonally adjacent cells.<\/p>\n

The solving logic is deeply satisfying. A 4 surrounded by four white cells forces all four to have bulbs. A 0 forces all adjacent cells to be empty. A 3 next to a wall (with only three adjacent white cells) forces all three. From these forced moves, the rest of the puzzle unfolds through elimination.<\/p>\n

Our RetroPlayNow version features puzzles at multiple sizes, a tap-to-place bulb interface, real-time conflict highlighting (bulbs that shine on each other glow red), and a satisfying light-spread animation when you solve each puzzle. Every completed puzzle earns Retro Coins.<\/p>\n

How to play Light Up<\/h2>\n
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  1. Illuminate every white cell.<\/strong> Place bulbs so that every white cell either contains a bulb or is lit by one horizontally or vertically (walls block light).<\/li>\n
  2. No conflicting bulbs.<\/strong> Two bulbs cannot illuminate each other. If they share a line of sight with no wall between them, that is a conflict.<\/li>\n
  3. Satisfy numbered walls.<\/strong> Each numbered black cell must have exactly that many bulbs in its four orthogonally adjacent cells.<\/li>\n
  4. Start with forced cells.<\/strong> A 4 forces all four neighbors to have bulbs. A 0 forces all neighbors empty. A 3 against a wall forces its three open neighbors.<\/li>\n
  5. Earn Retro Coins.<\/strong> Complete puzzles to score points based on size and solving time. Faster solutions earn more Retro Coins.<\/li>\n<\/ol>\n

    Frequently asked questions<\/h2>\n

    More games to play<\/h2>\n