Fang the Fox, rebuilt with Opus 5.5.

Back in 2022 I started Fang the Fox as a way to learn web development. By October it could move around, pick things up, heal and lose. The next items on the list were a level builder and a way to advance to the next level.

They stayed on the list.

This week I sat down with Claude Code running Opus 5.5 and asked for a redo with improved pixel art. What came back was a whole game.

It started as a remake and turned into a story.

The new Fang runs on a 384 by 240 canvas scaled up by whole pixels, so nothing ever blurs. Every sprite is drawn as a small text grid right in the JavaScript. The lighting is dithered, the islands float, and the rain splashes on the grass.

Then it grew. Twenty-four areas. Five bosses guarding five stolen Embers. Grandma Ember at the Hearth, Hoot the owl trading lessons for relics, Rudy and his gem shop. Braziers to light, blocks to push, ice to slide across. The whole Tiny Bit Adventures album plays underneath it, one track per part of the world.

A robot plays the whole game every time something changes.

This is the part I didn’t expect. Alongside the game there’s a bot that opens it in a headless browser and plays from the title screen to the credits. It pathfinds between islands, solves the puzzles, fights every boss and reports where it died. There’s also a map checker that proves every door, item and brazier can be reached.

A game this size needs its own tests. Without them, a small map edit can quietly make the ending impossible.

The review found a way to get stuck forever.

I asked for a review of what we had so far. The worst find was in the Void, the very last area before the final boss. A path of crumbling tiles was the only way across, and the tiles fell into the void once you walked over them. Cross before lighting the far brazier, and the gate to the final boss could never open.

The fix was tiles that knit themselves back together. Then the map checker learned to flag any crumbling path that cuts an area in two. The first time it ran, it found a second trap in the Dreamspace: a single square you could step onto and never leave.

A few quieter bugs went too. Story scenes used to fire on timers, so a boss’s farewell could pop up right over the death screen. Now they wait their turn.

Then came the polish.

Enemies in the dark caves were nearly invisible, so now they carry a little light and a faint moonlit edge. Every island used to be the same rectangle. Now each one has its own ledges, notches, underside and drifting rocks.

The sound needed the most work. We measured every track and every sound effect. The effects were sitting about ten decibels under the music, so you could barely hear Fang get hurt. Now every sound has its own level, the music dips under the big moments, and there’s an options menu for music and sound volume, screen shake and flashes.

You can play it right now.

Fang the Fox runs in your browser, on this site. Press Start and bring the fire home.