Atari 2600 programmers were absolutely amazing.
River Raid (by Carol Shaw) was a masterpiece of procedural generation. Pitfall (by David Crane) and Adventure (by Warren Robinett) were huge games (at the time) and fit into just 4096 bytes.
If you haven't read it, and have a passion for gaming history and computer hardware, I very much recommend reading "Racing The Beam", by Nick Montfort.
The 2600-era was magical.