I don't think anyone's saying you could do a cycle-perfect emulation on 8-bit. The framerate would be low, the terrain mesh would have to be much simpler. But The Sentinel[1] ran on C64 with acceptable framerates (better than a lot of 3D games with much simpler graphics). I think you could manage a perfectly satisfactory port of Asciiker, even with rotation.
Are you joking? The Sentinel takes 6-8 seconds to render a scene. The rest is just very clever 2D-scrolling and selective object insertion and removal.
Geoff Crammond (author of The Sentinel) wrote another game that's graphically way more impressive in this context: C64 Stunt Car Racer. https://www.youtube.com/watch?v=KMgjmIW8fd8
This is not to say The Sentinel wasn't an amazing game in all aspects, including graphically. It certainly was.
Yeah, like dropping rotation. I think it'd be easier to do 80x50 rendering than ASCII.
> The framerates were atrocious...
That's the sacrifice you'd need to make.