Storm the keep. Shatter the Emperium.

The Crimson Throne holds the castle. You are the Azure Crown's last champion. Smash through the walls, topple the Guardian Stones and shatter the Emperium, the crystal at the heart of the keep, before the siege clock runs out.

A castle siege in your pocket, inspired by Ragnarok Online's War of Emperium. Built for portrait phones with touch controls, and just as playable with a keyboard.

How to conquer

1. Breach the walls. Break the Outer Gate, or flank through a side Postern.
2. Topple the Guardian Stones. Their crimson links shield the Emperium.
3. Shatter the Emperium. Get past the Castle Captain and his ground slam, and brace for the reinforcements that pour out when the crystal is struck.

You have 10 minutes. Fall, and you rally at the furthest checkpoint you've won. Beat your best time and aim for rank S.

Choose your champion

• Knight: wide sword cleaves, and a shield that stops arrows. Whirlwind hits everything around you.
• Lancer: the longest reach in the army. Charge skewers a whole line.
• Mage: homing arcane bolts that burst on impact. Meteor Storm even cracks gates.
• Archer: fast, auto-aimed arrows. Volley fills the air.

Features

• A hand-painted castle with three ways in, side courts and a throne room
• Defenders that hold their posts, raise the alarm and hunt you down
• Hit-stop, crits, meteors, torchlight and shattering crystal
• Original synthesized soundtrack and sound effects
• Minimap, objective arrow and one-thumb auto-aim

Controls

Phone: drag on the left side to move. Hold the red button to attack, tap the blue button for your skill.
Keyboard: WASD / arrows to move, J or Space to attack, K or Shift for your skill, Esc to pause.

Made for Slapjam AI #1

Castle War was made in 48 hours for Slapjam AI #1. The theme was Castles, and we chose to storm one.

Team

• Yan Fróes: game director, design and playtesting

AI tools used

• Code: Claude Code (Anthropic, Claude Opus 5.5) wrote all of the game code, the enemy AI, the level and collision data, and the build tools.
• Art: the castle map was generated with ChatGPT image generation (OpenAI). The character sprites are human-made LPC pixel art (see Credits), combined and recoloured by a script written with Claude Code. Effects, the Emperium crystal, gates and UI are drawn in code by Claude Code.
• Audio: all music and sound effects are synthesized in code written by Claude Code. No AI audio models or recorded samples were used.
• 3D: none, the game is 2D.
• Other: game design ideas, this page's text and the screenshots' staging were done with Claude Code.