Yes, CHIP-8 is kind of the standard "I want to get into emulators" first project. In my latest book Computer Science from Scratch we go CHIP-8 -> NES in chapters 5 to 6. GBA is quite a step up from CHIP-8. I would suggest doing NES or GameBoy next, but of course with today's LLM help GBA is very reasonable if you are going that route.

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