Below is a list of all of the bullet upgrades that the player can find.
+1 Bullets, which provide a 25% damage bonus to bullets;
Angry Bullets, which cause bullets to re-fire themselves into nearby enemies, or in random directions;
Bouncy Bullets, which allow bullets to bounce off of walls and enemies;
Easy Reload Bullets, which allow the player to automatically reload a single bullet when dodge rolling;
Flak Bullets, which cause bullets to splinter off into smaller bullets upon hitting walls or enemies;
Ghost Bullets, which allow bullets to pierce enemies;
Heavy Bullets, which increase damage and knock-back at the cost of bullet velocity;
Katana Bullets, which, upon killing an enemy, gives a chance to trigger a flurry of wind slashes that damage and push other enemies;
Remote Bullets, which allow the player to control the flight path of bullets using the cross-hair and slightly increases damage;
Zombie Bullets, which provide a chance for missed shots to refund ammo.
Bloody 9mm, which provides a chance of a bullet being replaced with one that bounces off walls and homes towards and pierces through enemies;
Bumbullets, which provide a chance for angry bees to be fired out of the player's gun alongside a bullet;
Chance Bullets, which sometimes shoots bullets from the player's other held guns while firing a gun;
Charming Rounds, which provide bullets a chance to charm enemies;
Gilded Bullets, which increase damage depending on how wealthy the player is;
Helix Bullets, which doubles gun output but slightly reduces damage and causes bullets to travel in helical patterns;
Homing Bullets, which provide bullets a chance to home in on enemies;
Hot Lead, which causes some bullets to set enemies on fire;
Irradiated Lead, which causes some bullets to poison enemies;
Magic Bullets, which provide a small chance for bullets to transmogrify enemies into chickens;
Rocket-Powered Bullets, which increase the velocity of bullets, and slightly increases damage and fire rate;
Scattershot, which triples gun output at the cost of accuracy and damage;
Shadow Bullets, which provide a chance to fire an additional bullet for free whenever the player fires a bullet;
Stout Bullets, which significantly increase damage and bullet size at close range but decrease damage at longer ranges.
Alpha Bullet, which significantly increases the damage of the first bullet in the magazine;
Chaos Bullets, which cause bullets to do random things;
Explosive Rounds, which provide a small chance for bullets to explode on impact;
Fat Bullets, which increase the size and damage of bullets while slightly reducing max ammo capacity;
Frost Bullets, which provide a chance for bullets to slow and eventually freeze enemies;
Hungry Bullets, which provide a chance for bullets to become cannibalistic and destroy enemy bullets on contact;
Omega Bullets, which double the damage of the last bullet in the magazine;
Orbital Bullets, which cause missed bullets to temporarily orbit around the player;
Shock Rounds, which link all of the player's bullets together with lightning;
Snowballets, which cause bullets to increase in size and damage as they travel;
Blank Bullets, which give all bullets a chance to generate a short-ranged blank on impact;
Platinum Bullets, which slightly increase damage and fire rate for each bullet landed on enemies, up to a maximum of triple damage and fire rate.
- Most Bullet Upgrade sprites are designed after either pistol cartridges or shotgun shells, the exceptions being Silver Bullets and Chaos Bullets, which are designed after rifle cartridges.