Below is an ever-expanding list of interactions found by the gungeoneering community, whether they be positive, negative, neutral or maybe just a tad bit strange.
Positive Interactions[edit | edit source]
- Super Hot Watch allows the player to stack the 360 Yes Scope synergy's bonus indefinitely by standing still while spinning around, allowing the player to build up a massive blast of damage.
- The final shot of the Finished Gun always orbits when using Orbital Bullets, providing an incredible defense.
- Flak Bullets affects the bullets reflected by Casey. Flak Bullets also causes Casey to fire a spread of three high damage bullets when swung.
- Snowballets completely negate the negative effects of Stout Bullets.
- Revealing the contents of a chest using The Exotic while Book of Chest Anatomy is in the player's inventory gives a high chance of finding the revealed item upon breaking the chest.
- Rocket-Powered Bullets partially negates the negative effects of Heavy Bullets.
- Heavy Boots completely mitigates recoil, allowing the player to more effectively use Alien Engine as an actual weapon.
- Flak Bullets causes Alien Engine to fire bullets.
- With both Buckle Up and what engine do you use, Gungine has a chance to gain ammo when fired, because it shoots 3 bullets per shot and each has a chance to be refunded.
- Baby Good Mimic fires forever if the player has Shock Rounds.
- If the player has both Mimic Tooth Necklace and Ring of Mimic Friendship, all chests will be unlocked for free with the exception of Rat chests.
- Despite Lich's Eye Bullets not being able to replicate the dual-wield part of the Trigger Twins synergy, it can still replicate the synergy's other useful effects and increase magazine capacity and max ammo capacity.
- Elemental bullet upgrades (such as Hot Lead), cause explosive weapons to leave behind pools of elemental goop. The same applies to Mahoguny's pinecones.
- Short-ranged blanks (i.e those from Blank Bullets) have their knockback range significantly increased by Ammolets. That is, to say that the radial effect of the Ammolet spans the full room, but the blank effect doesn't.
- Bullets reflected by Casey are affected by most bullet upgrades.
- Cactus synergizes with Broccoli Twice, for the Cactus Flower & Vegetables synergies.
- If the player has both Full Metal Jacket and Elder Blank, FMJ will use Elder Blank in place of a regular blank if Elder Blank is fully charged when FMJ's effect is triggered. If the player has means to rapidly recharge Elder Blank they can become extremely difficult to damage.
Neutral Interactions[edit | edit source]
- Helix Bullets causes bullets reflected by Casey to travel a helical pattern without duplicating them.
- Bullet upgrades that cause bullets to leave trails behind them (i.e Battery Bullets and Cursed Bullets) allow the player to see the invisible bullets that are fired by Casey and Heck Blaster.
Negative Interactions[edit | edit source]
- The game will more than likely crash immediately if the player fires Black Hole Gun while they are carrying Helix Bullets.
- Angry Bullets and Ghost Bullets prevent explosive weapons, such as the Com4nd0 or RPG, from working properly, as the projectiles will bounce off/pierce through targets without exploding.
- Resourceful Sack and Bloodied Scarf prevent Rolling Eye from functioning, as the bullet stealing or dissipation prevents Rolling Eye from reflecting bullets. They likewise prevent Daruma from functioning.
- Sponge renders it impossible to restore ammo by reloading Gungine, Plunger, or Crestfaller with the Five O'Clock Somewhere synergy over a puddle of goop.
- If Baby Good Mimic transforms into a familiar that can either permanently die or sacrifice themselves to save the player (i.e. the police officer spawned by Badge, a turtle spawned by Turtle Problem, the Pig, or Ser Junkan in his Holy Knight form), Baby Good Mmic can permanently die as that familiar.
- Flak Bullets stops the EGG MURDERER synergy from working.
Odd Interactions[edit | edit source]
- The innate homing of Mutation displays unusual behaviour when combined with Ghost Bullets.
- The distortion effect of black holes stacks.