Good start! Does it support Cybergraphics 3 on classic?
It should work, the real job of this engine is to detect the system in which it is running, and use the correct functions to have a basic screen initialization, the use of double buffer, bobs, mod player, joystick and keyboard, without the need to use AmigaOS API that runs from classic Amiga systems to MorphOS with the same executable file. But checking my code, maybe it will fail using the fb_flush function that manages the double buffer, which only manages the MorphOS system, the classic kickstart version of less than 38 or the classic 38 biggest kickstart version. I no longer have a Cybergraphics system, I sold my BVision
If you have a Cybergraphics system, check the executable examples of the engine. If it does not work, I'll change it to be compatible.