Yes, the science could be sorted out pretty quickly. It's the story that counts.
The original's main problem was that, apart from its one interesting conceit, it really wasn't about anything and it had no story. It was just a chain of events with a few perfunctory sub-plots that were discarded almost immediately. It got by on a nice, slightly eerie atmosphere, good production values and Barry Gray's fine score.
It might have been more interesting if the mirror earth had differences beyond just sdrawkcab writing! I dunno... something... additionally.... unnerving....
I have it on good authority that they already made a remake on the other Earth and it tanked.
It could be a hybrid remake/sequel like the 1978 Body Snatchers; Roy Thinnes could make a cameo. They could obliquely indicate that he ejected from the ship at the end, and was living in the shadows as a normal resident on the "opposite" earth.
As for the story, well be honest, it's just an elevator pitch spread out over 161 minutes, that is TWO HOURS AND FORTY MINUTES without any "Transformer's" noise to shake you awake. The main actor's name is even: Keir Dullea, yes DULLea! D.S.
Similar ship and long trek in the Space:1999 episode "Dragon's Domain." The spaceship graveyard and monster were a better payoff, in my opinion, with some lovely stellar backgrounds along the way. Interestingly, it also used classical music.
Just want to embarrass my friend John Johnson for his generosity and kindness in treating me to a copy of this to cheer me up - hugely thoughtful of him and I'm so looking forward to seeing this very under-rated movie again.