Gameplay is absolutely atrocious by modern standards; ARPGs are a genre that really only got better with time. Soundtrack is unbelievably gorgeous and evocative, just try to forget that the composer is a netouyo now.
I don't like this game much myself (the humor doesn't really click with me, and I think it has pretty serious balance problems throughout), but I respect people who do.
I loved this game as a kid (the Mother Brain fight is a fond memory), but every time I play it as an adult I just like it less and less. The map design is very disjointed and Samus just doesn't feel fun to play as.