Codex Pet Arena

Build a playful single-player browser game called “Codex Pet Arena.” The player chooses one of eight original animated pets and competes against CPU-controlled pets in a large side-scrolling platform arena.

The main goal is to collect glowing Codex tokens placed across platforms, moving routes, hidden corners, and risky high places. Each token increases the pet’s score and gradually makes it bigger. Pets can bump or stomp one another, causing some tokens to spill out for anyone to collect. The biggest, highest-scoring pet should feel powerful and lead the leaderboard.

Start with a fun core: responsive movement and jumping, a scrolling arena, simple platforms, collectible tokens, and CPU pets that can move around and compete for them. Then add growth up to 3×, attacks, occasional power-ups, changing maps, and satisfying effects.

Use ImageGen and the hatch-pet skill to create eight original pets with distinct personalities and a small set of consistent animations.

Make the arena wide enough to explore in both directions. Add moving platforms, spring pads, shortcuts, hazards, and rewarding token routes. Change the map and rearrange the platforms every 30 seconds. Give different maps their own playful effects, including a Moon map with low gravity.

Keep the interface simple and let the game fill the screen. Add upbeat music, fun sound effects, particles, screen shake, and other small touches that make collecting tokens and hitting rivals feel satisfying.

Make it colorful, fast, slightly chaotic, and easy to understand within a few seconds. Focus on creating something genuinely fun and playable rather than reproducing every possible feature.