Faster, better. The Ataris had a very canonical screen layout which made it very easy to draw graphics, i.e. a simple rectangular screen array. x position shifted, plus y times bytes per row = screen address.
The C64 was good at character map graphics and sprites, but as soon as you had to render graphics for any kind of simulation (Rescue, soloflight, FS-II, the Eidolon, ...) it was quite horrible due to its non-canonical screen-addressing. You first had to find the 8x8 block on the screen the pixel lies in, then compute its address, then compute the position within the 8x8 block. This plus the lower CPU frequency typically slows such games down to a crawl.
In other words, the C64 version is a very good port.
ROF used to scare me to near death when I was a kid! As a kid I never figured out that the aliens had green heads when approaching your ship. But, even so, sometimes they're out of sight when walking towards your ship, so can still suprise the player.
Fantastic game, fantastic atmosphere - my favourite C64 game I think.
