I actually prefer Diablo 1 over the sequels. In the sequels, the character classes are over-tuned where you end up with certain metas or optimal builds. Diablo 1 doesn't do that. You kind of play along with what you get, maybe using spells as a Warrior or equipping heavy weapons and armor as a Sorcerer. Your journey through randomized dungeons with randomized loot is not about grinding to get optimal loot and keep leveling to unlock your specific class's skill tree to perfect your build. Your "build" in Diablo 1 is an emergent beast that is shaped by your unique journey, in part due to your decisions, in part due to the chances and opportunities created by the RNG.
In terms of game mechanics, Diablo 2 & 3 are way too obsessed with the loot. The hunt for incrementally better loot is supposed to drive you to continue playing. This does nothing for me. It's part of why I dislike most MMORPGs.
Diablo 1 even stands the test of time with really polished gameplay. The combat is fast and fluid, it starts out pretty tense as you progress down the levels and increase the difficulty. The lack of running makes exploration more tense, as you have to wonder if you're not walking into a deadly situation or ambush, forcing you to develop strategies and prepare for potential retreats. It only ever gets boring if you choose to lag behind and re-run things to grind. If you keep pushing yourself to new challenges, it never gets stale. The controls are responsive and the character customization and menus are simple and intuitive, still. A lot of games mentioned in this thread, existing at the time, were clunky and cumbersome. Daggerfall?! Don't kid me, that game's controls and bugginess made it a lackluster mess and it still is till this day. Meridian? What a flaming pile of garbage that was. I actually played those games back in the day, and the only other RPGs I appreciated and enjoyed playing and re-playing were the ones that had good polish. Yes, Might & Magic III & IV were great games, but they had ridiculous settings and next to no story. The games with good story usually had lackluster game mechanics or were exclusive to JRPGs. I'd say that Ultima 7 still gave Diablo 1 a run for its money in terms of story and theme while remaining mechanically interesting and polished. Eye of the Beholder I & II still work even today and I think belong to the few games that I'd even dare to compare to Diablo, though they are linear without much story to tell and built mostly on gameplay and atmosphere. And it took years into Diablo's lifetime until Ultima Online came out, becoming a complete triumph in its own rights.
Then there are aesthetic elements, like Diablo 1 being much bleaker and more medieval than its sequels. The more the series went on, the more I only came to think of it as "bubblegum fantasy with a dark slant." Yes yes, it's dark fantasy. Sort of. It's also extremely colorful with a lot of good-versus-evil stereotypes and increasingly outlandish mash-ups of fantasy tropes that become more pronounced as the series progresses. It also had to keep getting more over the top versus the more grounded and gritty scenario of the first game. Just compare the quests and ending in Diablo 1 to the sequels: there is no hope. The ending of Diablo 1 paints -you- as the monster, showing your journey of greed and carnage through the dungeons and into hell and slaughtering Diablo as a descent into madness and destruction from which there is no return. I appreciate Dark Souls as the actual spiritual successor to Diablo 1.
Finally, as other people have mentioned, the multiplayer aspect really sold it, originally. The reason I only go and give Diablo 1 short replays in the recent decade is because the multiplayer on battle.net is dead. Back in its heyday, it had a thriving community where people traded gear, chatted, exchanged strategies, role-played together, and played a lot of co-operative hunting and PvP (though a good chunk of the latter was akin to Dark Souls, with people "invading" games and hunting players). Again, this was before Ultima Online came out. The multiplayer turned Diablo 1 into a unique blend of excellent gameplay and multiplayer experiences that nothing even remotely rivaled at the time. Especially in terms of the tense multiplayer elements, I'd also cite Dark Souls as the spiritual successor to Diablo 1 in that regard.
Post edited June 18, 2019 by Wratts