Some perks are offered more frequently than others, and the probabilities are roughly as detailed below.
Standard Probability:
- Elemental Perks: Fire, Flamethrower, Poison, Ice, Zap
- Basic Shrapnel perks: Shrapnel shots, Sidewinder, More Sidewinder, Death Shrapnel, Frag Bullets
- All Death Perks
- Some Health Perks: LifeSteal, BandAid, Max Health Up, Tank
- Some Blue perks: Safety Bubble, Bullet Time, Dwarf, Triple Jump, Balloon, Heavy Armour, Hoarder, Dodge Master, Adrenaline
- Some White perks: Multishot, Double Barrel, Homing, Backshot, Vertical Shots, Buckshot, and Titan Heart, Shield, Armour
- Some Red perks: Berserk, Fast Shots, Focus Shots, Hit mark, Gun heart, Big Crit Up, Sustained fire
Less Common Perks
Chances are around x0.5 to x0.66 compared to the Standard:
- Blue Perks: Jetpack, Ninja, Fast Learner, Move Speed Up, Treasure Hunter, Haggler, Crafter, Springs, Time Stop
- Headshot
- Revenge
- Power Tripper
- Combat Medic
- Triple Barrel (only if you have Double Barrel)
- Flatulence
More Common Perks
Chances are around x1.5 compared to the Standard:
- Spread Shots (Max 3)
- Big Attack Speed Up
- Big Attack Up
- Chain Shots
- Bouncy Walls
- Improved ice / Fire / Poison
Rare Perks
Chances are around x0.2 to x0.33 compared to the Standard:
- Dividing shots (only if you have Chain)
- Super Homing (only if you have Homing)
- Croesus (only if you have Hoarder)
Very common Perks
- Piercing Shots (~x2 chance)
- Piercing Shrapnel (~x2 change, but only if you have Shrapnel shots)
- Titan Mode is a near certainty when you have the 3 pre-requisites
Note: These were calculated using a large number of runs in World 9 and 10 only, so they may be somewhat different in Events / Castles / Endless, or in lower worlds. Also the data collection happened over several bursts, so these might be inaccurate if the chances changed over that period (and they might change in the future too)