I played Diablo 2 first... before playing this game for the first time many years back... and while I was glad it spawned the sequel because D2 was a great experience I never understood why Diablo was so successful. I didn't really get into PC gaming until about '98 but I have gone back and played many games from throughout the 90s and compared to the other offerings available all throughout 1996 it surprised me that it was met with such praise.

One town.
One dungeon.
Three classes.


If I was a PC gamer at the time I would definitely have been too busy with Elder Scrolls II to bother with this game. Even going back some years before many CRPGs offered much more than this
Might and Magic: World of Xeen, Ultima VII, Menzoberranzan, Ravenloft, the Ultima Underworld series, etc.

That said, I loved Diablo 2 -- the exploration, skill trees (both totally absent in Diablo), and story (contrasted to most of Diablo's being contained in its manual) was all great fun.

It definitely lacks many things but IMO it has charm. The creators did a great job with D1 and D2 aesthetically, I love medieval horror and it's a theme that you don't see in a lot of games. I will admit that the gameplay is really nothing special, but I'm going to run through it once just because I love the atmosphere.

I believe it was to do with simplicity.

Diablo back in the day was easy to get into. Didn't require a beast of a computer to run and was rather cheap compared to other games.

There was no over complicated stats, magic or character build system.

Remember alot of old CRPGs back then didn't always work out of the box.

It also has great music and a great atmosphere. Voice acting was great and characters well written.

the main thing that made d1 so successful was online play, not only was it one of the first online games but battlenet didnt have a subscription cost

Diablo 1 took ASCII roguelike and brought it to the mainstream with realtime.
There's still allot of depth in D1 that was kind of lost with D2, like improving char/gear with shrines and the brutal nature of D1. Not that D2 isn't any of those things, but everything about D1 is more focused. Progression is simpler and immediately impactful.

I've been having a great time with this and I've spent many hours playing D2 and Grim Dawn. It's simple and fun. But back in the day there was nothing like having an ear collection of fallen opponents from PVP.

Atmosphere, first and foremost. The dark environment, the ominous soundtrack/music, the gothic lettercase even... This is one unique experience. Able to captivate even gamers of later generations. This gem not only survived the test of time, but is always, so hot! Even the voice acting adds to the whole picture.

Then, the soundtrack is great. Really great. Easily recognizable, decades later! A real shame GOG didn't secure the rights to its distribution too, honestly!

Strategic character build. You spend/allocate points manually, nothing is automated, like in WoW. You can even wear plate on your Sorcerer; talking about which, Diablo has "mageplates" (heavy armor designed for spellcasters), which have great design and grant your spellcaster player extravagant looks... Warrior and Rogue can use some basic spells, too, which diversifies gameplay and adds to the fun factor. All in all, the gameplay is spectacular, although simple.

Loot! Hunting uniques and working out item combos, is part of the build. Great variety, large utility, lots of stuff to try. You are never going to be bored.

Replayability. 3 difficulties and multi. Random dungeons. Always something fresh going on.

And for those back in the day, the nice artwork and hand drawn pictures, in game's manual. Signed by Metzen, if memory serves? Plus, the story found there. Almost generic, quite simple, not complex or convincing at all, but very inspired.

"Simplicity reigned supreme", in one sentece. Practicality, in one word. Kill, loot, town portal, vendor trip, rinse and repeat, the magic formula!

Mood, atmosphere and simple, quick efficient gameplay.
Multiplayer, too... i actually never played this in single player mode.

The gloomy atmosphere, simple but addictive gameplay, a great soundtrack.
You don't always need a lot of different ingredients to make a tasty pie.
And it was a different time. The pie selection back then wasn't as excessive as it is today.

In my opinion Diablo did not age that well though. Sure, it's still fun to run through it a few times, but it gets boring fast and it's very obvious a lot of things could have been improved, even back then.
The frustratingly slow walks in town, spells and arrows often missing due to this 'tile' system or however you'd call it, needing to spend eons getting to level 50 in single player due to the lack of difficulty modes.
(Yes, I'm aware Hellfire fixed some things.)

Even though Diablo 2 improved on many things, I still find Diablo having a greater atmosphere. It's so grim. The corpses in hell and the Butcher's room are the stuff of nightmares. And the end video is very dark.
And I kind of like that Diablo 1's selection of unique items is a lot smaller. Diablo 2 is an unstoppable grind fest, you will never find every item that you'd like to have, unless you give up your social life (and possibly your job) and grind for 12+ hours per day (or, like me, create a mod so to force the game to spawn unique items).
Diablo is less bad in that regard.

IIrc it wasnt a full price game. The graphics were good for 1996. 3D cards didnt become mainstreem before the following year.

This was a couple of years before Baldurs gate, so there wasnt too much 2D competition. MMOs didnt exist*, so the online/Lan co-op was where it was at.

*I know about MUDs. They weren't mainstreem for good reason.

You could do LAN play with only one copy of the game (thanks to the spawn feature), and you didn't even need a proper LAN - you could daisy chain the PCs using serial cables.

There was nothing else like it. When I first saw preview screenshots for the game, I thought it looked terrible. But I was sold the moment I saw gameplay footage at the game store. There were not a lot of real time games back then - real time in the proper sense that you can get in trouble and can't even pause to consume items.

The lighting effects were also pretty revolutionary. Posts above have talked about how important they were to the game’s mood, which is definitely true, but they even had actual gameplay relevance. They are primitive compared to today’s effects, but at the time most dungeon crawlers either ignored lighting altogether or made it binary - you either had the “light” spell cast and could see everything, or you didn’t and could see nothing.

Most important was the random level generation. There were other games that did that, but I certainly didn’t know of any at the time. The idea that you couldn’t look up a map for a level somewhere because it literally didn’t exist was incredible. It also gave the game replayability like no other game I had ever played.

For me it's mostly the small things like:

- "no automap in town" -> mandatory exploration in order to locate all NPCs
- no "hey dumbass, I've a quest for you"-floating exclamations over NPCs heads -> mandatory interaction with NPCs in order to get quests or information on quests
- spells for specific purposes -> e.g. Holy Bolt works best against Undead but doesn't do shit against the Not-Undead
- enemies with actual immunities for specific damage types
- arrows (or projectiles in general) actually move at a "realistic" velocity
- no highlighting loot on the floor
- complete randomness to shrines and their benificial or detrimental effects (unless you memorize what each shrine does)
- "cursed" items that give maluses when equipped
- and a couple of other little things

I know.
One of the side quests that unfortunately got canned for the release version also revolved around weakening Diablo before the final confrontation.

It wasn't really a side quest, more like you just had to finish the last level of the game within 60 minutes or Diablo would be a lot stronger (to the point where he was practically undefeatable).
It was lame and didn't serve much of a purpose, better off being removed.