You can also try your hand at programming a virtual 2600 at 8bitworkshop, along with other consoles and platforms. With my interest in this area, I can't believe I hadn't heard about 8bitworkshop until just the other day: it is amazing!

https://8bitworkshop.com/v3.10.0/?platform=vcs&file=examples...

Updated this month? Incredible that people still see value in this so many years later!

Pikuma also has a course on Atari and NES programming