Turns the nuclear artillery shells on/off. Thunderfist do more damage, as well add damage over time to the units in the target area and take longer to recharge.
Firestorm Shell
Turns the firestorm artillery shells on/off. They load faster than nuclear artillery shells and deal slightly less damage.
Deploy
Enables/Disables the stationary artillery fire. The damage of the artillery gun is greatly increased but the unit is no longer moveable.