For example, House Harkonnen may be able to construct their Devastator tanks with heavy armor and ordnance but cannot build the similarly impressive Atreides Sonic Tank. The Ordos have access to the Deviator - a specialized tank firing a nerve gas that switches the allegiance of targeted units to Ordos for a limited period of time. The three Houses also are restricted in their production capabilities—House Ordos cannot build Atreides-style trikes, instead making the faster "Raider" trikes, while House Harkonnen constructs heavier but more expensive quad bikes. A player can gain access to other Houses' special units by capturing an enemy Factory and manufacturing the desired units at the captured Factory. Buildings may only be built in rocky zones and connected to another existing building. To protect them from constant wear, the player must first place concrete slabs in the construction areas. Production buildings can be upgraded at a cost several times, allowing the production of more advanced units or buildings. The final prize for the commander is the building of the House Palace from where superweapons may be unleashed on opponents in the final closing chapters of the game. The House Harkonnen superweapon is a long-range powerful but inaccurate finger of missiles called the Death Hand, whereas House Atreides may call upon the local Fremen infantry warriors, over which the player has no control, to engage enemy targets. House Ordos may unleash a fast-moving Saboteur whose main purpose is the destruction of buildings. The AI of Dune II was one of the first used in RTS games, and while better than that of Herzog Zwei, it has various drawbacks. Examples include only attacking the side of the player's base facing its own, general inability to perform flanking maneuvers, and not rebuilding defenses. Research into the game's engine revealed that the AI is in fact capable of more advanced strategy, but that a large part of these capabilities is unused due to consistently repeated errors in all of the game's mission scripts. Development According to Virgin Interactive vice president Stephen Clarke-Willson in 1998, the development of Dune II began when Virgin Interactive planned to cancel the production of Cryo Interactive's adventure game Dune, after which he was given the task of figuring out what to do with the Dune license. After reading the original Dune novel, he decided that "from a gaming point-of-view the real stress was the battle to