A guy who started working as a game programmer for Atari when he was 21 years old recounts his experiences, notably his work on the Donkey Kong cartridge.
Basically, Atari’s marketing folks would negotiate a license to ship GameCorp’s “Foobar Blaster” on a cartridge for the Atari Home Computer System. That was it. That was the entirety of the deal. We got ZERO help from the original developers of the games. No listings, no talking to the engineers, no design documents, nothing. In fact, we had to buy our own copy of the arcade machine and simply get good at the game (which was why I was playing it at the hotel - our copy of the game hadn’t even been delivered yet).