This engine was once based on churrera 3.99.02, but has long since outgrown it to the point where it became a separate engine. You can disassemble and check. We plan to release our engine as open source in 2024, and of course it will be noted that it has some roots from Churrera 3.99.02. But first we need to remove the Duck Tales specific code from it so that it looks more like an open source engine ready for building other projects and not just an open source Duck Tales game.