The Busters in the Ghostbusters franchise suit up with possibly one of the heaviest backpacks designed for catching ghosts as part of the iconic ghost-busting gear set. In Ghostbusters: Spirits Unleashed, players get to upgrade their primary equipment as they level up for better busting builds, and this includes the widely recognized high-tech Proton Pack strapped to a Buster's back.
The Proton Pack has 4 upgradable features: the Injection Booster, Generator, and Cyclotron, and each have 4 build upgrades to construct the best Proton Pack, although the choice available depends upon player ranking and Research Contracts completed. The Proton Pack gives the iconic Particle Thrower its juice, so it's a crucial component in any player's build when playing as the Buster. However, choosing between upgrades can feel challenging, with each upgrade possessing pros and cons. This list highlights the best proton pack builds to make player choices easier and quicker.
6 Efficiency Optimizer
When it comes to efficient Injection Boosters, the Efficiency Optimizer is arguably the best choice. When compared to the Default Injection Booster and the Energy Isolator upgrade, the Efficiency Optimizer is better at keeping the Proton Pack cool, so it may not overheat as quickly with its pluses in Heat Generation. This includes when the ghost is tethered and trying to escape like the nimble, widely recognized Slimer, one of many iconic ghosts.
However, keeping cool comes at the cost of reducing Tether Creation Speed. Although the Efficiency Optimizer can potentially help keep the ghost tethered for longer with reduced overheating effects, its overall tethering ability may not be as effective as other Proton Packs.
5 Centrifugal Thruster
The Centrifugal Thruster is an alternative Injection Booster but is only available to players who have completed the Centrifugal Thruster Research Contract, unlockable by sprinting for a total of 15km with the Particle Thrower.
It has additional pros and cons compared to the more readily available Default Injection Booster and Energy Isolator, which are both evenly matched in stats, except for the Energy Isolator being the better choice for Rift Damage. The Centrifugal Thruster is not as good for Rift Damage and managing Heat Generation, but has additional Movement Speed and Firing Movement Speed, giving busting a speed boost.
4 Cyclical Exhaust Port
The Cyclical Exhaust Port is one of the best Generators to use in any Proton Pack busting build as it offers all the benefits of the Default Generator including Rift Damage and Idle Cooldown Speed, plus a boost to Venting Speed. This means when busters use their Particle Throwers to shoot a rift or a ghost, cooling the pack by venting is much quicker, which is useful when trying to destroy a rift quickly or tether a fast, evasive ghost.
By comparison, the Lightweight Module is lighter to carry around and faster to maneuver with a boost to Movement Speed, Mantle Duration, Stamina Usage, and a handy perk of additional Self-Revive Speed, but it's less effective when it comes to tackling rifts.
3 Governor Release
An alternative to the Cyclical Exhaust Port is the Governor Release Generator, unlockable by completing the Governor Release Research Contract by revealing 25 rifts and dealing 5000 rift damage using their Particle Throwers. It's similar to the Cyclical Exhaust Port with its Rift Damage and Idle Cooling Speed, but it contains an additional 2 pluses to Overheat Protection, helping the player bust ghosts and rifts for longer before the Proton Pack overheats.
On the flip side, the Cyclical Exhaust Port does have reduced Venting Speeds, but if players are cautious and keep track of the heat meter and press X on an Xbox controller to vent the Proton Pack regularly, they shouldn't need to worry about a slower venting speed.
2 Enhanced Regulator
When it comes to Proton Pack cooldown efficiency, players can look to the Enhanced Regulator Cyclotron for one of the most efficient pieces of cooldown-busting tech. This is because it possesses increased Cooldown Delay, making the Proton Pack cool much more efficiently which, is handy when using the Particle Thrower while tethering or damaging rifts.
In contrast, the Nitrogen Tank Expansion offers similar stats, except for its increased Idle Cooldown Speed. It, therefore, depends on the player's preferred play style as to which Cyclotron build to go for, as the Nitrogen Tank Expansion and Enhanced Regulator match each other equally in remaining stats.
1 Cryogenic Isolator
The main perk of the Cryogenic Isolator is its 3 pluses to Sabotage Repair Speed, which is a handy upgrade when tackling ghosts keen on sneaky Proton Pack sabotage. It's also a decent alternative for the Cyclotron due to its increased Overheat Cooldown Duration, albeit at a slight cost to Venting Speed and Idle Cooldown Speed.
If players are keen on safeguarding against sabotage, it's a great choice compared to the more basic stats of the Default Cyclotron. However, to unlock the Cryogenic Isolator, players must complete the Cryogenic Isolator Research Contract by overheating while tethered 15 times and venting the Proton Pack while above 90% heat levels 25 times, which is risky business, and likely a challenge for even the most skilled of Busters.
Ghostbusters: Spirits Unleashed is available to play on PC, PS4, PS5, Xbox One, and Xbox Series X/S.