I remember playing this as a kid in 1999. For some I thought it was very hard. I was still pretty young, but while I found Warcraft 2 and StarCraft challenging, I remember them being easier to eventually figure out.
The story/lore also felt more immersive and realistic. Very grim dark and even scary. This might be a controversial opinion, but I always thought that Blizzard's story beats were generally subpar. They excelled in game design, balance and visual art, their writing was never impressive.