Zombies have 500 health on normal, and 1,000 in nightmare, so for charging weapons is twice as long;
The max charge power is 3.5, and you gain 0.571 per second, you can charge for 6.13 seconds
(the max carrying mass is 10 kg)

Important and useful information

• Bleeding does 1 dmg
  
• 5% chance of bleeding from injury
  
• 15% chance of bleeding from injury when below 45 health
  
• bandages stop bleeding and give an additional 15 health
  
• medkits give 30 health and stop bleeding if you are
  
• Screen turns gray at 35 health (I'm 99% sure)
  
• Fire does 1 dmg/unit
  
• Molotov fire does 3 dmg/unit
  
• Electrocution does 25 dmg/unit (or 100 in some cases)
  
• Barricades have 150 health
  
• Infection takes 120 seconds to kill
  
• Pills stave off the infection for 200 seconds
  
• Gene therapy has a 10% chance of blinding you for 60 seconds
  
• Zombies can't survive longer than 10 seconds on fire
  
• Flare guns do 50 damage, and molotovs do 30 damage
  
• Gas cans do 8 damage
  
• Zombies can reach 44 inches (3.7 ft [about 1 meter])
  
• Molotov damage radius is 96 inches (8 ft [2.4 m])
  
• Molotov burn frequency is 0.5 seconds
  
• Molotov damage duration is 20 seconds
  
• Grenade blast radius is 256 inches (21.3 ft [6.5 m])
  
• TNT blast radius is 512 inches (42.7 ft [13 m])
  
• TNT shake screen radius is 2048 inches (170.7 ft [52 m])
  
• Probability of zombie dropping loot 10%

List of zombie damages

• Bites always do 15
  
• Hits always do 15 from regular zombies
  
• Runners do 20 and 40 damage for 1 and 2 hands respectively
  
• Kids do 8 and 16 damage for 1 and 2 hands respectively

Here is health fraction of zombies

fₘ = infection chance modifier (0.975 on casual and 0.14 on nightmare)
fₕ = health as a fraction
(You are twice as likely to get infected in survival mode)

P = (1 - (fₕ ⋅ fₘ))²


My calculator (theoretical)[xyzpw.github.io]

My theory is fall damage is (25/55) ⋅ (V - 480)

Because half-life has the same formula, but the multiplication factor is different, and it matches up with maximum fall velocity to 100 dmg and minimum 0; which, g = 20 m/s^2

I've messed around with crouching and it never seems to increase stamina regain, so that's most likely a myth.

Stamina cost list

• Stamina cost is 2-fold when bleeding
  
• Shove cost 20
  
• Jump cost 20
  
• 12 per second when sprinting
  
• Not moving regain rate 12
  
• Regain rate crouch 9
  
• Regain rate moving 6
  
• Light breathing plays at 80 stamina
  
• Medium breathing plays at 60 stamina
  
• Heavy breathing plays at 40 stamina
  
• Maximum stamina is 130