sounds like an MMORPG Jr.
Except it has a real plot, and probably the best item system I've seen in any game ever (compared to most MMORPGs who are basically "you hit level x, now you can wear armor set y. Maybe if you get really lucky you'll drop a piece of armor or a weapon that has some sort of stupid useless magical effect, like +2 damage on something that does 250 damage !")
Not to mention the game is based around killing horeds of relatively easy to kill monsters, as opposed to most MMORPGs which are based around monsters being tough enough to require being taken on one at a time, and such.
D2 has a totally different feel from MMORPGs today. Plus, you can go through the plot in 3 different difficulties, and play on Hardcore mode, where if you die, you are permanently dead, but get bonus items/exp for doing so.