What Are Synergies?
The Gungeon has a wide range of secrets, including hidden passages, tucked away rooms, and entire secret dungeons. Most of these secrets aren't for the benefit of the player, though, requiring extensive work and increased difficulties to reap their reward.
One secret, however, is entirely for the benefit of the player - Synergies. Synergies are special combinations where, when certain items are used in tandem, dramatically increase their power and effectiveness. These Synergies are notated with blue arrows above the player for a short duration, showing that this combination is in effect.
Utilizing these synergies can result in easier runs, quicker room clears, and easier boss battles.
1 - Pea Shooter / Broccoli
The Pea Shooter seems an odd choice when considering the best weapons for the Gungeon, but there's a good reason it's part of this list. While the gun shoots very low damage bullets, it receives some pretty significant boosts when paired with the Broccoli passive item.
First and foremost, Broccoli triples the damage output of the Pea Shooter, bringing the damage to just over normal. Most importantly, however, is the fact that the Broccoli also increases its rate of fire, turning a relatively slow rate of fire, low damage weapon to a quick repeater.
That's not the main benefit, though - Broccoli triples Pea Shooter's damage, increases its rate of fire, and makes its shots pierce. This piercing quality all but negates a lot of the defensive qualities of enemies like Bosses, significantly magnifying effective damage, even when the theoretical damage is limited.
2 - Frost Giant / Heart of Ice
The Frost Giant is already a pretty powerful weapon, firing large bullets and creating a temporary freezing cone that stops many enemies in their tracks. This weapon is best used in boss fights where smaller enemies are spawned, and can make short room of even the most crowded, intense rooms.
The true potential of this weapon, however, comes when it's paired with the Heart of Ice. First off, there's the built-in benefit of the extra heart granted by the Heart of Ice, which is powerful in and of itself. Going further though, the interaction between these two items greatly increases the size of the freeze cone when fired.
What this means is an effective increase to not only survivability through the extra heart (and the added benefit of bouncing ice bullets firing off when you take damage), but to effective room control, allowing you to freeze more and negate greater amounts of enemies.
3 - Dueling Pistol / Ballot
The Dueling Pistol is a Gungeoneer favorite, firing off musket balls that bounce two times off of walls, obstacles, and cover items. This makes it great for dealing damage not only when you miss, but when your enemy is around a corner, and exposing yourself establishes too much risk.
This main benefit is drastically boosted in this synergy with the Ballot item. Simply put, bullets from the Dueling Pistol now bounce five times instead of twice. While this is a small change, consider the fact that blindly firing into a group of enemies with a double bounce shot gives you three chances to hit (the initial shot plus the extra two), an increase of 200% from the base chance to hit. Shooting with six chances to hit (the initial shot plus five more) grants an increase of 500%, meaning that your bullets can miss FIVE TIMES before it's considered a "wasted shot".
This means, simply, your effectiveness is no longer determined by your aim, but instead by your positioning, removing a huge amount of burden from each run.
4 - Demon Head / Pitchfork
The Demon Head is one of the more powerful weapons one can obtain in the early floors of the Gungeon. Even forgetting the fact that it's essentially "hold and forget", allowing a Gungeoneer to simply hold the fire button and allow the beam to trace the room, the fact that it has the chance to inflict burn, and thus heavy damage, makes it incredibly powerful.
The only way this could get better is to add piercing, which is exactly what the synergy with the Pitchfork does. By adding piercing to a high-range, continuous damage weapon, you get a huge boost in not only damage, but in effective range - just keep the enemy somewhat in sight so that you can ensure you're making contact. You can be clear across the room doing huge, continuous piercing damage, while also likely inflicting burn.
5 - Various / Muscle Relaxant
While the Muscle Relaxant is by itself a powerful item, granting a pretty hefty increase in accuracy, which is especially useful with ranged weapons, its true power is when it's paired with a small set of weapons:
When paired with these weapons, the Muscle Relaxant greatly increases damage. For certain weapons, like the Crossbow, this takes a weapon with already insane accuracy and damage, and makes it a straight-up godlike visage. With the Hexagun, a weapon with piercing bullets that occasionally transmogrifies enemies, you add on piercing damage to the already ridiculous increase, allowing you to one-shot even late floor enemies.
Paired with any of these weapons, the added accuracy and damage augments singular effects like the Crestfaller's freeze ability, creating a weapon that is simply overpowered in the best of ways.
First in a Series
Keep in mind that these are simply four extremely powerful synergies that have been recommended by the community - there are a ton more synergies within the game, and we're going to feature more in this series. If you know of a great synergy, let us know in the comments or forums. If you don't? Get in the Gungeon!
For more gameplay tips, check out the Official Wiki, packed to the gills with secrets, references, and guides to surviving the bullet hell onslaught. Want to chat up some fellow Gungeoneers? Head over to our forums!