Don't bother with D1, just go for D2. Still easily one of the best games ever made IMO, pretty sure I played that game well over 2000 hours.
Diablo 1 has some amazing atmosphere that Diablo 2 just seems to lack.
However gameplay wise Diablo 2 is a huge step and improvement. They are really different games entirely.
Diablo 1 focused on suspense almost like a horror movie, slow movement, dark catacombs with creepy as **** music.
Diablo 2 focused more on action and a "open world" feeling with varied locations - The gameplay and skill tree was so amazing that WoW Classic used it.
Diablo 3 is.... well lets not talk about that game.
I agree, D2 is your best game to try. Try some interesting building like Dagger Necro or a Dragoon Barb. Whirlwind Sin? So many builds!!!!!!!