According to norecess464, he has said SonicGX was first previewed at the Alchimie XIII (1st of November 2019) as a work in progress game for the Amstrad GX4000 and Amstrad Plus Machines. He goes on to say the game features full-screen game-play at full-framerate (50hz) with approx. 40 colors on screen with other previews released at some point to a full release of the game planned for the end of 2020.
Programming : NoRecess / Condense
Graphics enhancements : CeD / Condense
Audio : Targhan / Arkos
Support & Testing : TotO, Overflow, Longshot
Links :1) Source