Conspiracy theory time from YouTuber Larry Bundy Jr who suggests Elite re-skinned two canceled 16-bit Thundercat games as other titles. In one case not even taking the theme tune out.
You'll have to skip to 13m25s to get to the point but the argument is compelling. Elite made one Thundercats game, The Lost Eye of Thundera, which was released, and two more that were promised but never appeared.
Of the two, one was released as Beyond The Ice Palace after an unsuccessful attempt to sell it as a sequel to Capcom as a Ghosts 'n Goblins sequel, while the second apparently became Bomb Jack 2. The evidence: firstly the music is the actual Thundercats theme tune with the composer stating that it was used to "save the work that had already done on it". Then there's the fact that the main character sports Lion-O's orange hair and blue leotard combo while holding a not very Bomb Jack sword. Once you've got that in your head then it all starts to look a bit Thundercatsy - from the Slithe like creatures to the slightly sci-fi backgrounds.