Saw this for the first time in years last night. Given that it's an 80s action movie and there was no CGI used in it (afaik), it's still an entertaining action film. The production quality is actually pretty high, even by today's standards, and the performances of Willis and Rickman hold up really well. I remember seeing it when it first came out, and it was a blockbuster!
The reason it looks better is that there is no CGI. The stuff we see blowing up and falling is all actual stuff, whether full-scale or models, so it doesn't have the CGI "video game" look. Another reason is that during action scenes, including fights, there are often shots that last several seconds, rather than just an exhausting montage of half-second cuts. As for the performances of the actors being good, that's no surprise at all. Actors in movies have been giving great performances for a century. In spite of what we've been brainwashed to believe, acting wasn't just invented by Robert De Niro, or even Marlon Brando.