The Unearthed Hack includes quite a few additional rules for The Black Hack that make it well worth the money. There are two suggested ability arrays with point buy alternates that give it a 3.5 or 5E feel of That Other Game and two different takes on Races: race as class and the more traditional race with added abilities and bonuses. The races are different enough from The Race Hack that you can get four different ways of implementing races or borrowing their suggestions and making your own. I enjoyed the section on monster groups and multi-staged boss fights; those will be fun to incorporate into my own game. FInally, there's the magic item section that definitely has a Diablo-esque vibe to it with bonuses or extra abilities receiving its own special title.
There are two things that detract from this title. The largest is the Combat section: I am not a fan of flipping the table, so to speak, and changing how the dice work in the first method of PvP, but there is an alternative given as well. The level drain segment seems unnecessary for my game, but if that's a significant area for you, then that guideline is there. The second comes in Character Creation: The Allure attribute is effectively a derived Comeliness attribute. Again, I do not need it, but it is there for those of you that do. And lastly, it is listed in the Race section that Humans have access to luck points, though I do not see anywhere in the book where or how luck points are generated and used. If I were to guess, it would probably be a once per day thing or, borrowing from the fifth edition of That Other Game, an inspired thing.
All in all, the title is worth the asking price. There are many recommendations in the game that will find its way into my game.