This is coolest visualizations of code and data inside an Atari 2600 cartridge I’ve seen. It is amazing to see the branching in the code segments. I can only imagine how painstaking it must have been to do by hand. However, I doubt if they had much of an alternative. Programmers were dealing with very little memory.
However, one should be able to tell by just looking at the picture that developers for pac-man were having some problems. Here is a video of how the game actually played.
Q-Bert, on the other-hand, has some bugs, but still, what the developers were able to do is pretty impressive.