If Doomsday Perk is selected, whenever your hero lands a nuke that would count as a surgical strike, the CP base will automatically immediately launch a nuke at a nearby enemy structure. This nuke lands much quicker and does no friendly fire. A nuke is considered a surgical strike if it deals at least 2500 damage and causes no friendly fire.
Additionally, minerals will be refunded based on 3 x sqrt(damage dealt) by the doomsday nuke and provide the "Surgical Strike" talent automatically.
The Doomsday perk automatically provides the Surgical Strike talent, which will refund 3 x sqrt(Damage) worth of minerals (minimum 150) for both the normal nuke and the extra doomsday nuke.
The doomsday nuke upgrades based on game time:
- +110 structure damage every 4 minutes, up to +3300 at 120 minutes
- Massive Blast after 40 minutes
- Electrostatic Fallout (+1500 Psionic, +900 Heroic) after 80 minutes
Note that bonus damage is averaged between the highest and the lowest bonus if it matches a unit, such as Heroic Structures like Hives. This means that peak damage for a doomsday nuke occurs at 76 minutes before the nukes are upgraded with +900 Heroic damage, which cuts the damage down from 600 + 3290 (structure) to 600 + [3400 (structure) + 900 (Heroic)] / 2.