If you download the 2D shmup template project from
here it seems like in the media folder (probably an images or logos sub folder) I included a few different sizes of the AppGameKit circular logo just save folks some time from scaling and sharpening.
I like the AppGameKit logo personally. Nice visibility good readability.
Anyway... I am not sure if the background color / gradient would matter. I would donit. Just use whatever background I wanted just wouldn't change the logo itself.
Personally what you did seems fine to me but I guess ask them. I wouldn't think your updates would break brand recognition. Honestly hardly even noticed what you did if anything myself.
TI/994a (BASIC) -> C64 (BASIC/PASCAL/ASM/Others) -> Amiga (AMOS/BLITZ/ASM/C/Gamesmith) -> DOS (C/C++/Allegro) -> Windows (C++/C#/Monkey X/GL Basic/Unity/Others)