Avernum 5 - Interview @ RPG Vault

Jonric: What's the basic structure? Is it more linear or open-ended, and is it possible to arrive at different endings?
Jeff Vogel: The game is mostly linear, but there are many side quests and interesting choices the player encounters while hinting the assassins. Also, they might attempt to recruit you. And, in typical Spiderweb Software fashion, switching sides and joining the rebels is a viable option. Because of this, there are quite a few possible endings.