The original games used a two-dimensional grid-based graphical system, effectively displayed as an X-Y axis wherein each tile in the grid was filled by a base graphic and perhaps an item or character icon. Avernum has a 45-degree isometric display that appears more three-dimensional, allowing for more advanced terrain through the addition of a vertical axis.
With the design overhaul came improvements to the graphical user interface (GUI) and to the storyline as well. While primary plot devices remain relatively unchanged, many new encounters and side-quests were added. In-game art by Phil Foglio lends a more humorous feel to the game.
Avernum, like Exile before it, is demoware. The user can download the program, and play a significant part of the game without restrictions, until he or she advances to a certain point in the storyline. By paying a registration fee to the creator, the user gains access to the full game.
Avernum. The first game of the Avernum trilogy sees your newly created characters thrown from the world above into the subterranean world known as Avernum. Once here you discover a culture that has formed from the outcasts of the Empire above: a culture beset by constant warfare and monsters galore. In Avernum you meet with many who wish to get revenge on the Empire for the wrongs it has done to the Avernites.
Besides countless side quests along the way, the game offers three primary quests: killing the demon Grah-Hoth, discovering a route back to the surface, and assassinating Emperor Hawthorne of the surface world.
Avernum 2 takes place five years later. The Empire recognizes the threat the Avernites pose and begins sending their army down into Avernum in huge numbers. To make matters worse, unknown barriers of energy are sprouting up around the world - sometimes aiding the Avernites, sometimes helping the Empire who can afford the losses much more easily than the Avernites.
A new party of characters meets one of the creatures causing the barriers sprouting up in Avernum, and go to meet with the unknown race to try and secure an end to hostilities. In the end the party is successful - and the Vahnatai join with the Avernites to drive out the Empire. With the support of the Vahnatai the Avernites turn the tables on the Empire and successfully repulse their invasion.
Avernum 3 takes place four years after Avernum 2. A lot of preparation has taken place and now the Avernites are ready to send a selected few back into the light of the surface. After those selected few vanish, they send a selected few more. While you are at first stunned by the sheer beauty of the land around you, you begin to notice that things are not as perfect as they seem. The slimes you encounter are only the first part of what becomes a series of monsters and terrible occurrences that are blighting the Empire and laying it to waste. When scouting the land, as per your orders from the Avernite government, you are asked by the Empire to help save the surface from its blight. You bring the Avernites and the Empire together once more as allies trying to find the cause of the destruction.
Its most notable feature is a free scenario creation kit that can be downloaded and used to make adventures that can be distributed to other players. It has come under fire for being "too complex" in comparison to Blades of Exile, its predecessor, which used a very simple instruction list instead of a C-derivative script system. On the other hand, it has also been praised for allowing many new possibilities using said script system, which couldn't be achieved with the Blades of Exile system.
Spiderweb Software has released the source code for the editor and allows others to make enhanced versions and add-ons, which a number of players have done. The most notable adaption of the editor is a 3D editor, which allows the user to view and edit a project using the isometric in-game view.
Avernum 4 was released for Macintosh in late 2005 and released for Microsoft Windows on March 2, 2006. It uses a new engine created by merging the Geneforge and Avernum engines; essentially this means that the gameplay is entirely turn-based, but uses the Geneforge point-and-click navigation and user interfaces. In addition, there is a large amount of new art in order to bring the world of Avernum to life within the reworked Geneforge engine.
Avernum 4 takes place long after the others - one of your dialogue options remarks that the events of the third game happened "before we were even born". Weird monsters have been appearing in the underworld, and three powerful undead beings have been attacking random people in the cities. Once again, the player takes charge of a group of heroes which will, in the end, determine the fate of all of Avernum.
After completing the Windows version of Avernum 5, Jeff Vogel will begin work on the final game in the Geneforge series. No word on Avernum 6 has yet been released.