That’s gameplay from the just-launched mod, The Curse of Tristram: Destruction’s End. It attempts to recreate Diablo II in Starcraft II. That’s seven player classes, three difficulty modes, co-op, new random global events, and most of the main story campaign. Creator Etienne Godbout has been working on it for four years and while there are still some bugs, and it’s definitely a beta, it’s an impressive effort from a lone modder. Doubly so, when you consider the Starcraft II engine is being stretched to the limit to make this work.
The Curse of Tristram is now available in Starcraft II’s arcade mode.