Like all science fiction it makes some assumptions and then explores what these would mean. The assumption here is that memories and identities can be implanted in a human. Some people may think this is just round the corner, they probably thought so too when the film was first made. The fact that it is still a long way off, if it ever is possible, means this film still works as science fiction. Add to that the fact that they have colonised Mars and we haven't managed the moon yet, and it looks as though it has plenty of life.
Of course it has Arnie in the lead role so if you're not an Arnie fan it may not be for you. There is plenty of action and some twists so it is entertaining enough. After the film you can ponder the questions the film asks. What makes personal identity? Does an implant change a person or just the way he behaves. It comes from an original P.K. Dick story, not as good as Blade Runner but entertaining enough. One interesting point was that their autonomous taxis had dummy taxi drivers, whereas we seem to be able to manage driverless vehicles without a panic attack.
As the other review said, this film is 30 years old, but if you're a science fiction fan (or an Arnie fan), it's an enjoyable romp.
This has to take the title for the best cheesy Arnie one-liners ever :D
The next time I click 'Contact Us' on a website and get a bot saying 'I'm sorry, I did not understand your query', I will be asking it if it is Johnny-Cab.
I'm not sure the 4K version adds anything tho