I have a very vivid memory of renting an animated Ultraman movie some time during the early/mid 80's. My memories however do not seem to match up with any of the animated Ultraman media of the time.
As I recall the movie starts on a space ship after a battle in which "Ultraman" apparently was killed, there may have been a flashback to the battle. I think another member of the crew (maybe a woman) becomes "Ultraman" for a time with the real "Ultraman" returning by the end...maybe.
I remember the animation being very dark, noir-like. I specifically remember "Ultraman's" body lying on a table or a stasis container/coffin in a dark and shadowy room, not sure if he was gigantic or human sized.
I also remember getting a bit bored, because there was a lot more talking than action.
As I said I would have been between 6 and 10 when I saw this so my memories could be spot on or completely wrong.