Ghosts are support units. Their attack and health are unremarkable for their cost. Their weapons deal concussive damage, which is ineffective against large units (e.g. siege tanks and ultralisks) unless massed, which is usually unfeasible due to their high tech position, cost and build time. Ghosts are a poor choice for large-scale combat due to their expensive cost and fragility to many attacks and spells such as spawn broodling, psionic storm and irradiation. Ghosts are also fairly slow which leaves them vulnerable to units like vultures and mutalisks.
Ghosts are best used for their abilities. Their lockdown ability, while micro-intensive, is devastating to mechanical and robotic units.
Defensively, dark templar make good counters against ghosts, especially when they attempt to use the nuclear missile ability.
The ghost also has its own death sound that is in the game data, however it is not implemented into the gameplay. Instead, a recycled and slightly altered marine death sound is used.
The ghost disables enemy mechanical or robotic units. Targets may not attack, move, or use abilities; passive detection and cloaking are disabled. Lockdown may be removed by a medic's restoration ability.
A ghost launches and "aims" the nuclear missile at a targeted location. The missile arrives 10-15 seconds after. The ghost must aim for the entire duration; if the ghost takes any other action, or the ghost is killed, or the missile is cancelled, the launch is aborted and the missile is wasted.
The launch is broadcast to all players with the audio and visual message "Nuclear Launch Detected." The targeted location is visible to all players as a small flashing red dot.
The missile deals 500 damage or removes two-thirds of total hit points (whichever is greater) to all units within a wide blast radius. One nuke kill most units, and critically damage most buildings. Two nukes will destroy nearly anything. Without Ocular Implants, the ghost's targeting distance is within the blast radius.