Cobra / ZX Next

Cobra was the reason to learn the ZX Spectrum Next as a working game platform, rather than as a piece of nostalgia.

I wanted versions that could preserve the original behaviour, improve the original experience, and use the expanded capabilities of the Next. That meant understanding both the game and the machine closely enough to make deliberate differences.

Public AI knowledge about the platform was weak because the platform is niche. I assembled my own technical sources. The available emulator tooling still left a larger gap: it could not properly debug the language and workflow I was using.

I added the developer debugger to the existing JNext emulator and contributed it to the public project. I also built the source-map and source-level infrastructure needed to connect the running machine back to the game code.

1. 01Build the game
2. 02Find the tooling gap
3. 03Add the debugger upstream
4. 04Reuse the common systems

As Cobra developed, movement, asset handling, debugging, build steps, and other patterns began repeating. Rebuilding them for every title would waste the work already done and make each game harder to verify.

The ongoing work is becoming an engine and toolchain for related games. It grows from working game code and working developer tools, rather than from an abstract engine designed before its uses were known.

JNext is a public ZX Spectrum Next emulator for developers. The debugger was my addition to that existing project. The current emulator includes machine-wide inspection, backwards execution, layer views, headless automation, and tooling aimed at game development.