A classic RPG set in an underground world, Avernum IV is a fantastic game. In it, you control a guild of up to four characters, which can be customized both in appearance as in abilities. Each character levels up individually, getting a few points which you can then spend in their abilities; and, as a classic RPG, there's plenty of them: from combat abilites (including things as melee combat, ranged combat, etc) to magic (two types, actually, one focused on magical attacks, and the other in buffs and debuffs) and "social" stats like luck and charisma.
The game itself is played on an isometric view, and the combat is turn-based: your characters (and the enemies) have a set of movement points, which are used to perform actions during your turn, from moving (duh) to combat and magic. As you explore the world, there's always the possibility of random encounters. Depending on where you are, and the skilll of your characters, these can go from minor annoyances to incredibly intense battles. You can go pretty much anywhere, and the game world is rather big, but you can increase the speed of the game in order to move faster. Even then, there's no fancy fast travel, although you do get a boat.
The story is quite good, given the fantasy world setting: you're in this huge underground world known as Avernum, where people exiled from the topside world learned to live, and a huge threat is beginning to show up. You start as a group of regular soldiers set in one of the furthest outposts, and you must make your way to the capital as you uncover more and more about the sinister forces at play.
Very good (and long!) game, I enjoyed it a lot. Recommended.