Black metal tends to have faster, repetitive guitar playing, higher pitched vocals, often with anti-religious lyrics, and constant blast-beat drumming. Production favors low end, for that raw in-the-middle-of-the-forest-running-around-like-trolls sound.QUOTE]
That basically sums up the criteria of the "tr00 black metal" out there. And is extremely accurate. There are exceptions, however, to every genre - as it seems there are various forms of death or black metal - but the typical attributes and common fundamentals of either genre are as described previously.
When I mentioned that there are "various forms" I meant for the following: Technical Death metal (or BM), Melodic Death metal (or BM), progressive death metal (or BM), etc. As there are bands that have obvious influences from either genre but don't really follow the traditional guidelines of the common black or death metal group.
These bands are much better than their counterparts who follow the abused formula of either genre. Borknagar and Arcturs to name a few. Arcturus being one of the absolute best "progressive" or "metal" band out there. You won't find many bands that experiment and change their sounds as often as these masters do. I highly recommend them.
Morbid Angel is another band said to be among the best Death metal groups in history. While they're over the top and are relentless with their constant assault on the listener, they're not your average "Death metal" group. They're highly skilled on their instruments ... which is lacking in the majority of typical death or black metal.
My rant has gone on far enough. But let me add one thing, Death ... yes, the Chuck Schuldiner led group, is NOT a death metal band. Where people ever got this idea is beyond me. I could honestly care less about the classification of any band, but if you must classify them, do so properly by observing their music.
Early Death was similar to Death metal, but around "Spiritual Healing" and especially on "Human", they are nowhere near Death metal. Chuck's music was constantly evolving, however, it grew in complexity and technique more so than it did for brutality. It was Technical Metal at it's fullest. Yet if you must categorize them in any of the basic metal genres it would easily fit under "Thrash metal".