When a target has its Hit Points reduced to 0 by an energy weapon, this perk will trigger an explosion centered on the target, similar to a plasma grenade explosion, but smaller. The explosion can cause critical hits and sneak attack criticals, potentially killing nearby targets and propagating further meltdowns.
- The weapon depicted in the Vault Boy icon is the Plasma Defender.
- The player character and companions can get hurt from the Meltdown effect.
- The damage dealt by Meltdown is relative to the damage dealt by the weapon that killed the target. A powerful weapon, such as the Gauss rifle, can trigger a meltdown dealing upwards of 300 damage, whereas a flamer's meltdown would be closer to 11.
- The meltdown explosion appears to carry any additional effects of the weapon that triggered it, such as igniting enemies, and any critical kill effects (enemies critical killed by a laser triggered meltdown become ash, while a plasma triggered meltdown produces piles of goo). This, along with the damage correlation, may indicate that the game treats any enemies struck by the explosion as if they were hit by the triggering weapon itself.
- All weapons affected by the Energy Weapons skill trigger the meltdown if the player character causes the killing blow. This is contradictory to in-game loading screens which say the perk affects only laser and plasma weapons.
- Meltdown does not exacerbate the impact power bug of the Gauss rifle or YCS/186 but somewhat remedies it by changing the trajectory of the corpse or causing the impact force of the shot to dissipate when the energy explosion occurs.
- Meltdown explosions will frequently dismember limbs, making this perk desirable when dealing with ghost people.
- Only the initial hit of a weapon can trigger Meltdown from killing an enemy. If a weapon has a damage-over-time effect (such as the flamer or holorifle), it will not trigger Meltdown if it is the cause of an enemy's death. It also appears that the "bonus damage" of the pulse gun will not trigger meltdown.
- Weapons which fire in "bursts" in V.A.T.S. can trigger multiple explosions. If an enemy dies before the final shot in a burst, each subsequent hit in that burst will cause another explosion.
- Meltdown does trigger when using Euclid's C-Finder, making it capable of killing enemies it otherwise could not.
- If Meltdown occurs with the Compliance Regulator, it is possible to paralyze the Courier as well.
- Due to the erratic and explosive nature of this perk, it may become difficult to find and loot the enemy's body after a Meltdown explosion.