So far it's a lot of the same, but with a drastically different visual style to it. Yea, it's slightly different in that the enemies melee you and are slow, but that just feels like it makes it easier. I sort of wish the zombies would shamble toward you though. Instead they do like a slow motion run (except for the crawling torsos that... crawl). A lot of the time it feels too easy because the number of zombies isn't enough to make up for the fact that they're slow and only melee you (some do spit/vomit, but it does little or no damage and instead it obscures your vision and slows you). But then I remember I'm playing this alone, and more players = more enemies. Also there are some scripted points where you'll get zerged and it's more hectic.
I can't help but compare to Diablo and Diablo 2's expansions. I don't remember a whole lot from Hellfire (for Diablo 1) other than adding the monk class. In Diablo 2 though, runes were added as a second type of item you could socket into equipment, along with rune words for multi-socket items, new item modifiers were added giving variety to the loot in any portion of the game, 2 new classes were added, and of course Act 4 was added. The big thing about that comparison is that once you bought and installed the D2 xpac, it changed the whole game, not just the new area. The Borderlands just adds a new area to play through, and when you're in the other areas it's as if you never bought the DLC.
I do have a thing for zombies though, so just the creepy atmosphere and the zombie hordes make it worth playing.
I don't think the perfect zombie game will ever exist. I think Left 4 Dead is the closest, but falls short in a lot of ways. If you took L4D and made the zombies slow, added more of them, and then add some barricading aspects, you'd be a lot closer. The only times I've seen anything like this has been in poorly done mods or indie games, and aren't FPS so they lack that satisfaction in shooting the zombies.
