I remember being tremendously disappointed with this movie when it came out (well, actually I checked, and the day it came out I was at a Dead Kennedy's concert, so I probably wasn't thinking about it much). I was completely disappointed when I got to see it, though.
They say you either love Bakshi's films or hate them. I loved the first three or four, and was prepared to write 'Lord of the Rings' of as an over-ambitious mistake. In fact it turns out that Bakshi made at least one film between LoTR and Fire and Ice which I did enjoy, but it was never released here at the time. 'Fire and Ice' is fantasy again, but instead of the original, not entirely serious, underground, big-hearted fantasy that worked so wonderfully in 'Wizards', or the Tolkien adapation of LoTR which might have been great if it had actually worked, 'Fire and Ice' is a descent into puerile, sterile by-the-book sword and sorcery which lacks any wit, brains or charisma.
In the years since 'Wizards', Ted White had made 'Heavy Metal' magazine hugly successful. It was a sort of mixture of French material (which tended to be surreal or at least cerebral and enigmatic), and American material (which was often good, but at its worst was dumbed-down adventure yarns for 14 year-olds in the vein of Sinbad.) Unfortunately the latter is the style of story which 'Fire and Ice' emulates. You remember the 'Gor' books by John norman? If you liked them you'll probably like this. Enough said, probably.
At the time, or soon after, I seem to remember I read an interview where Bakshi claimed that this was his best film, and that finally he had achieved the fantasy movie he had always been wanting to make (I think he's revised his opinion about his best movie since.) Frustratingly though, many critics at the time seemed to agree with him. To me the film just had no brain, no heart, it was Robert E. Howard style sword and sorcery, not particularly well executed. It was something anyone could have done, whereas nobody but Bakshi could have done 'Wizards' or 'Heavy Traffic'.
The animation is not impressive. You could forgive this in earlier films because there was so much else to like about them, but this time around the film had nothing else to prop it up. There is extensive use of rotoscoping, which gave the film a 'realistic' rather than a 'cartoony' look. Personally I don't watch cartoons for realism, so this was another drag for me. It did provide an amusing anecdote though. Co-producer and character designer Frank Frazetta, very famous at this point for his sword and sorcery drawings of horses and voluptuous women, is supposed to have had a revelation via rotoscoping. "I never quite realized how I was exaggerating the female form," he said. "In the back of my mind I always believed there must be women out there who existed like I draw them."
I really can't find anything to recommend about 'Fire and Ice'. Despite the fact that it saw a recovery of sorts in Bakshi's fortunes at the time, it's a basic, dumb, Conan-like story - he even re-used the 'Nekron' character name from 'Wizards') - and the disappointing animation makes it look terribly dated today. The audience it was intended for in 1983 probably wouldn't give a toss about it today, and neither, I suspect, would most other people else.
Ignore this rubbish and go watch Bakshi's 70's films, which are terrific.