Battlecruiser (StarCraft II)

The battlecruiser is the toughest terran air unit.

Wings of Liberty
In the Wings of Liberty single-player campaign, battlecruisers can be upgraded with the defensive matrix and missile barrage abilities originally included in the multiplayer game. Unlike during development, once these upgrades are purchased all battlecruisers have access to them in addition to the yamato cannon, rather than needing to be upgraded with a single ability in the field.

Development
The terran battlecruiser used to fire multiple laser bolts, each inflicting low damage. This attack could only target one unit, but once a target was dead, the rest of the blasts immediately moved to the next target, thus wasting no attack on any already-dead target.

The battlecruiser's abilities have undergone some changes in development, such as replacing its Plasma Torpedo ability with a Missile Barrage ability. This was changed as the plasma torpedoes did splash damage, thus overlapping with the role of the siege tank.
 * Plasma Torpedoes: An area-of-effect air-to-ground weapon which dealt damage over time and was effective against weak swarming units (like marines and zerglings). It added multiple small barrels to the front of the ship's hammerhead.

Abilities Removed By Beta
The weapon options other than the Yamato Cannon were removed from multiplayer by the beta. Blizzard found players rarely used the other options, and so they needlessly added complexity. However, they will be available in single-player. The Weapons Refit upgrade name was recycled for the Yamato Cannon upgrade.

Each version of the battlecruiser was treated as a different unit for UI purposes; double clicking on a Yamato-equipped battlecruiser would select all such battlecruisers but would not select battlecruisers with the Missile Barrage upgrade.