Darvond: For those who can't click or can't be bothered, can someone summarize what the Hell is The Hell 2?
The Hell 1 is/was the most popular mod for Diablo 1: Hellfire, basically adding so much extra stuff that its closer to Diablo 2 than the game it requires to run with. The Hell is in active development for over 8 years (AFAIK) and really adds lots of new things to the game to make it even more fleshed out.
The Hell 2 is basically the same with all aspects vastly improved, lots of other stuff added thats not in the previous mod such as new monsters, classes, items and dungeons. The biggest feature of the new Hell mod is that it can run at native 4k now without any hassle and also has functioning multiplayer. Consider The Hell 2 kinda like "the next step", which is very similar to what Terraria updates represent. So overall, the game got much larger in scale overall.
If its not enough of a description just ask and I explain what kind of stuff got added and changed from the regular game.