Surfing around I ran into this page here. Some amazing guy has enhanched and recoded much of Ultima III for the c64.
So much so, he compressed the original two disks into one disk. Apparently the code was really bad, they left most of the Apple II stuff un optimised, the text notes that the graphics were internally in Apple II format in RAM and were converted on the fly each time the tile was blitted to the screen.. Yikes. No wonder it was super slow.
Anyway, this version plays so much sweeter.
I also like the removal of the forced Sosaria world map save!
He also did a huge multi year project on revamping Ultima IV for the c64 :) (same website).
-- Stu --
He sometimes posts in various usenet groups and really knows his stuff.
And he did what Origin (and their contractors) should've done: Intelligent conversions.
The original C64 version of U3 surely wasn't optimized but at least it looked like Ultima.
Sadly, the same can't be said of the Atari 400/800 conversion which uses artifacting colors
(= bad colors on NTSC, black & white picture on PAL displays).
Any volunteers to make some worthy Atari versions? ;-)