Diablo is an isometric (3/4 perspective) single character Role-Playing Game(?). It seems more action oriented to me, but there is supposed to be NPC interaction also. From the makers of Warcraft I & II. Each game is randomly generated for maximum hack and slash variety. The game is specifically made for multiplayer and will be playable over the internet with Blizzard's own free battle.net server.

Release Date - Ready to go but waiting for Battle.net <-- from OGR

There is an good preview at Gamespot.
They also have a trailer but it is only cutscenes.

Screenshots

from Gamespot

A humongous Diablo screenshot #1
A humongous Diablo screenshot #2 both from Online Game Review.

Diablo Playable Demo, around 69 MBytes worth of download, requires DirectX2, Windows 95.

Ok, after waiting for a couple hours for the download to finish, i've finally gotten to play this game. It's worth it, go get the demo. The fighting is smooth and easy to use. There ARE stats, leveling, and all the good stuff you'd expect from an rpg. The music is moody, the graphics are excellent, speech is well done, and the action is great. I can't wait until the multiplayer version comes out... wow! In the demo, you can only play the fighter guy and there is only one level, but imho it's well worth the download (esp. if you're waiting like me for Bethesda to release some patches before playing Daggerfall seriously again). Start dling after midnight and you'll have a great demo waiting on your harddrive by the time you wake up :) (note: this is more of an action game, hack and slash, etc.)

A good Diablo page is at the Diablo Download Page. It also has a link to the new demo which allows you to play all three characters. (11.14)