Armored Core Raven may be happy to know there's a Diablo 1: Hellfire mod. Personally, I think he should play Torchlight, which is an unashamed homage and spiritual to the Diablo series. It combines and even upgrades the best bits from D1 and D2 (they even got rid of that awkward inventory system). Best of all, it's downloadable onto consoles.
D1 and D2 are very different beasts, but both celebrated classics, nonetheless, and have more than a few imitators (Phantasy Star Online is pretty much Diablo 1 IN SPACE, plus more races). Not all of these utilise the random dungeons thing, which is a real shame because the randomisation of levels and monsters is what keeps the games less predictable.
Here's a comparison:
Diablo 1 had Sorceror (magic), Warrior (melee) and Rogue (ranged). They could all do the same stuff like use swords, bows and the same spells but each class was an expert at something. For example, a warrior could still use spells, but not beyond a certain grade. There was a degree of compatiblity between the different classes and their gear
It was real easy to get into. I still remember my first Unique item: the Constricting Ring, which slowly sapped your hp while reducing all elemental damage to a quarter. The Hellfire expansion introduced the Monk, who was kind of a magic/melee hybrid. He could use staves, usually a Sorceror thing, more adeptly at melee, so much that he could strike two foes at once! Unfortunately, he's not canon
Then you got Diablo 2, where Blizzard expanded the three classes into 5 then 7, utilising different specialties and all with their own unique skill sets.
In the vanilla version of D2, you have 2 melee variants, 2 caster variants plus the Amazon who's pretty much an upgraded Rogue . Barbarian was offensive focused warrior while the Paladin was a defesnive focused warrior who projected auras. The spellcasters are the Sorceress (fire, ice, lightning, the usual) and the Necromancer (poison, summoning minions, non-elemental magic and curses).
Next, is Lord of Destruction, which introduces a new chapter, plus two more classes. The Assassin is pretty much a dual-wielding magic warrior whose fighting style can be summed up to punch-punch-punch-kick, but she has an array of traps and bombs at her disposal (one of the more common builds). Lorewise, she's supposed to be a an anti-magical warrior, which is ironic because she has some pretty magical skills...
Then there's the Druid. He summons minions, he can throw fire and tornadoes and he can morph into werebeasts for special melee attacks. In other words, he's the jack-of-all-trades-but-master-of-none class.
In D1, you gained and leveled up your skills by using Books, which each needed your character to have a high enough Magic stat to use. In D2, there are no books. You gain a skill point for every level up and use them to unlock and upgrade skills. Some skills require others to be unlocked.
Not all skills are worth it, admittedly. Some skills in the skill trees are clearly just tacked in, like Poison Dagger (requires a melee weapon on a squishy wizard class) for the Necro, and Apocalypse for the Druid (meteors hitting random spots on the ground every few seconds, not necessarily on to top enemies) and Holy Bolt (somehow not as useful in D2) .
But if done right with the right builds, you can make the most of your skill points, like a trap or a minion/curses build (cursing your enemies makes it easier for your skeletons and golems to stay alive).
These days and over a decade after the original release date, and just like Total Annihilation which I mentioned in the obscure games thread, there's an active modding community for these games. It all makes me wish I could learn to mod D2 and make my own classes, lilke turning the Necro into a proper Death Knight. All tehse fantastic things done by people who have the time and talent