For those who've never played it, Zangband is a variant of a game called Angband, but it's set in Roger Zelany's Amber world. Angband itself, is what is called a Rogue-like game. Minimail graphics, but lots of fun play, based on a game called Rogue. The first real dungeon crawler I believe. At it's most basic, it uses ANSI characters, but there are some other tilesets that slightly improve that. ZangbandTK is a graphical update to the game Zangband. Basically, it adds a different tileset and view to the game.
As for the gameplay itself, it's real simple. You create a character, from 30 races, and 11 classes. There's 7 different magic systems, as well as tons of weapons and items to discover. Zangband also differs in that there's an actual aboveground wilderness to explore, as well as the standard dungeon levels, filled with monsters and treasure. Levels and treasure and monsters are randomly generated, though as usual, you only get the good stuff the deeper you go. There is a point to the game, though in all my time of playing it, I've never gotten to it, it's almost un-needed. On level 99 there is one you need to kill called Oberon. Once he dies, level 100 opens up and you can go kill the
Serpent of Chaos, upon who's death you get the game title of Winner.
These kinds of games were what inspired Diablo, and it's various clones. Personally, I prefer these. Yes, they're not pretty, but they have immense replay valure and are just damn fun when it comes to building up your character. The games are one of the few I know of that have permadeath to them. If your character dies, that's it. The savegame is modified to show you're dead, and you have to re-make your character. No going back 5 minutes to your last save to avoid your mistake, whether it be falling through a hole to a room full of Jellies, or being ambushed by a horde or rats. Adds to the suspense of playing.
All in all, I recommend this game highly, especially if you like older games with more replay value than eye-candy.