Hey there, thanks for the feedback.

If you want to look at gameboy development, the setup used is fine for getting your feet wet, but you should ultimately switch to assembly as soon as possible. The used compiler (SDCC) and the library (GBDK) are full of quirks and bugs that mess up your perfectly fine C-code so working with it can be quite an bad experience. (Being new to gameboy dev I spent hours searching for bugs in my code that actually weren't my fault in the end, just as a warning before you step in). Nothing beats seeing your own game run on the real hardware though!