The following section contains information from a previous version of StarCraft II which is no longer valid.
Wings of Liberty Alpha and BetaEdit
Blizzard worked on the queen for two years. Previous versions of the queen actually produced units, but since there could only be one queen, this left the zerg unit production system too vulnerable (as the queen could be hunted and killed).
The intention behind the visual design was suggesting that the more developed zerg were beginning to mimic Kerrigan, thus the queen has a more feminine quality to her, as well as the dreadlocks and back-wings. Once designs were starting to hone in on the roles of the Zerg Queen, the final art pass was implemented. Interestingly, when the development team designed the queen, the cinematics department applied cosmetic improvements to the design which were then reflected back on the in-game model when it was finalized.
One unforeseen revision needed for the queen was in regards to the green sacks along her abdomen. Initially these bubbles were team-colored, but during playtesting the queen was actually looking very similar to the Zerg Infestor from certain angles and the two were getting confused. Henceforth, the team color was removed and the green bubbles returned for the final version of the queen.
The queen used to evolve over the course of the game, growing in size as it did so. Morphing to the Large Queen required a lair, while the Huge Queen required a hive. If the queen dies, it can be produced again at the hatchery/lair/hive with any existing upgrades. The queen no longer does this.
Lost Spawning Structures AbilitiesEdit
The queen used to spawn numerous types of structures upon the creep. Creep does not belong to any one player, which gave the queen the ability to spawn structures upon "enemy" creep in enemy bases. This ability has since been lost.
The queen had base defense duties, including laying eggs that hatched into suicide attackers.
Heart of the SwarmEdit
In the June 2012 build of StarCraft II: Heart of the Swarm, the queen had small changes in its appearance, making her similar to the broodmother. This was later reverted in Versus, but the model was used for the swarm queen.