The following section contains information from a previous version of StarCraft II which is no longer valid.
The thor has had a long and complicated development process.
When the idea was first pitched, the thor was going to be a super tank. Other ideas followed, such as making it a mech with tank-treads at the waist, and then finally the designers with the decision to make a giant mech. This unit was pitched to the artists at Blizzard and they received a mountain of concepts later showcasing multiple interpretations of what a giant mech should look like in the StarCraft universe. The first rendition stayed faithful to the concept from Samwise Didier. However, he tore into it. Everything changed, parts were moved around, proportions adjusted, silhouettes completely rearranged and a totally different piece of artwork emerged.
Several of the new terran units introduced in StarCraft II were given a sleaker, more advanced design, in order to showcase the technological progress the terrans had made since the original game. The thor was an exception to this however, for in the words of Samwise Didier, "thors don't need no girly design."
The thor was in the game engine as early as 2006. It was much bigger than its later forms back then.
In early builds, the thor could be constructed by SCVs in the field, though is now built from the factory. The thor "structure" used to cost 300 minerals/ 300 gas/ 6 supply/ 100 seconds, hotkey T.
The thor had a slow turning speed in the BlizzCon 2007 build, enabling units such as the cobra to destroy it easily with micromanagement. It now turns fairly quickly, and the turning speed is no longer a balancing factor.
The thor was scaled down in size as it was vulnerable to being subject to micro from smaller units that could be built in only a fraction of the time and resources required to build a thor. In StarCraft II beta patch 12, the thor was shrunk from a 1.375 base to a 0.8125 base size.
Previously the thor could not be transported.
Initially the thor had an ability called Immortality Protocol, or Mechanical Rebirth.
The thor can self-repair. Once a thor "dies" in combat, its wreckage remains on the battlefield. The terran player can spend resources to rebuild it relatively quickly. The enemy player must decide either to destroy the vulnerable wreckage or to target other units. The ability must be researched.
The thor lost the Mechanical Rebirth ability for multiplayer by May 2009. Blizzard's internal playtesting showed the ability to be impractical. It was retained as a campaign ability in Wings of Liberty.
Thors were to receive a similar emergency repair ability in Legacy of the Void. This ability deactivated the thor, preventing it from moving or attacking, while rapidly repairing it until it reached full health. This ability had been removed by February, 2015.
250mm Cannons (Previous Version)Edit
Artillery Strike was a powerful long-ranged area-of-effect attack. To use the Artillery Strike, the thor had to expend energy, then it "stabilized" itself as the cannons on its back were lowered. The four 250mm bombardment cannons alternated raining damage upon the area. This ability needed to be researched. The ability was later removed as it conflicted with the siege tank's splash damage attacks.
Anti-Air Flak CannonsEdit
The 250mm Cannons was once replaced by Anti-Air Flak Cannons during WWI 2008. They provided the thor with a powerful anti-air attack that did splash damage. They were visually identical to the 250mm cannons but did not require the thor to stabilize itself or expend energy in order to use them. This attack was later replaced by the thor's current 250mm Strike Cannons along with Javelin missiles that enabled the thor to retain its anti-air capabilities.
Heart of the Swarm ChangesEdit
At BlizzCon 2011, players were only be able to build one thor in Heart of the Swarm. It had stronger defenses, lost its anti-air attack and dealt more anti-ground damage. It had a powerful area-of-effect bombardment ability, but this required a setup time. The thor was moved into the late game, requiring a fusion core. The new thor cost 600 minerals.
By June 2012, the thor had reverted to its previous incarnation.
As of December 2012, the Heart of the Swarm version of the thor lost its 250 mm cannons and became larger. Instead, it can switch between two modes, a process that takes 4 seconds:
- High-Impact Payload: The regular mode.
- Explosive Payload: It fires 250 mm Punisher Cannons against air units; they have 10 range and deals 24 damage.
In Heart of the Swarm, the thor prioritized air vs ground targets. High Explosive Payload mode was added, allowing the Thor to do extra damage to air units.