What they did with Psycho Mantis was really interesting, watched it on a YouTube stream packed with MGS fans, most of which hadn't seen this before and they were all surprised by it, that was a treat. It's genuinely just interesting seeing a different take on MGS1's story, I don't regret giving it a watch.
That said, even though the way they merged the good and bad ending together was really sweet, Liquid Snake's fight scene and death were the lamest thing imaginable, and they cut the car chase out, come on!