Interesting to see this take the same approach as Wolfenstein did: each unique column height had its own dedicated blitting function. This was pretty much the only way to get "real time" on a 286-level PC in the past.
This level of 3D was not really done on Apple II's, however. There were wireframe games like Stellar 7 (similar to BattleZone) and flight simulators. Walk-down-the-streets between-buildings type games were 2.5D; no real perspective, 90 degree turns only, from what I remember. These machines run at 1 Mhz, with multiple cycles per instruction, and no cache. Not that it would help, since memory keeps up with the CPU, lock step.
Yep, IIRC that technique was novel to Wolf3D and before that you'd either have free-walking wireframe or 2.5D like you said. Seeing it backported to the Apple II is really cool.