The Apple II computer had a successful run from 1977 to 1993, with Choplifter, a game created by Dan Gorlin in 1982, standing out as one of the best games on the platform for sixteen years. The game was developed before good development tools existed, yet its smooth chopper control and physics show Dan Gorlin’s efforts in tuning the gameplay. The author reverse-engineered Choplifter to understand its inner workings, using tools like Virtual II, HexFiend, and da65. Starting from the keyboard handler code, the author deduced the game’s structure, showcasing the technical and game design brilliance of Choplifter.
https://blondihacks.com/reversing-choplifter/