Arcade Game Designer v0.7.10 is a Windows (32/64) utility by Jonathan Cauldwell to write games for Timex/Next, ZX Spectrum, Amstrad CPC, Acorn Electron, Dragon/Coco and Enterprise, without any knowing of programmation.

The big news for the CPC is that it should now allow you to import third-party assembler routines and call them in your game with the USER command (plus an optional argument that gets passed in the accumulator). There is an example user routines directory with a couple of routines suggested by users.

There is a forum about AGD, follow the link of the first message to download AGD.