Guide that tries to explain how the power ups work. Also was a part of a bigger project that aimed to explain all the mechanics, but it's unfinished so i'm just posting this small portion instead for now

Power-ups are rewards that zombies randomly drop when killed. In the shop you can buy and select which power ups can appear in the match. The first power up in the shop is always free. Some power ups have a duration lasting effect which last 30 seconds (Bottomless Clip, Fortify, Chronopulse, Necrovore, Zillionaire and Insta-Kill) or have an immediate use (Max Ammo, Vitality Surge and Nuke). If the power-up gives an ability to a player, it will only give it to the one who picked it up. Power-ups dissapear after 60 seconds if no player picks it up

• In-game description: Refill all ammo
  
• Functionality: When picked up, the player gets all of their weapons refilled to max including the loaded mag/clip.

• In-game description: Kill all zombies
  
• Functionality: When picked up, it explodes into a big flash and all of the zombies that are currently spawned are instantly killed. All of the money that is dropped by the zombies receives the player that picked up the nuke

• In-game description: Zombies die in one hit
  
• Functionality: When picked up, the player is given a red aura around them and is awarded the ability to one hit kill zombies. When combined with Bottomless Clip, the aura becomes pink until one of the powerups end.

• In-game description: Unlimited ammo
  
• Functionality: When picked up, the player is given a blue aura around them and is given an endless ammo reserve. This will work regardless of magazine ammo count. When combined with Insta-Kill, the aura becomes pink until one of the powerups end.

• In-game description: Inflicted damage heals you
  
• Functionality: When picked up, the player is given a white aura around them and is given the ability to heal by inflicting damage upon zombies sapping life energy. This gives you invincibility as long as you're killing zombies faster than being damaged. Rebound damage from the perk "Vengence" does not effect this drop.

• In-game description: Boost your health & speed above max
  
• Functionality: When picked up, the player is fully healed and given to 2 extra hits (that do not regenerate) until being killed. The player is also given a slight speed boost. The effects last as long as the player has the health bonus.

• In-game description: Double money
  
• Functionality: When picked up, all money the player receives is doubled. The money counter also becomes orange for the duration of the power up.

• In-game description: Repairs & electrifies all barricades
  
• Functionality: When picked up, all barricades around the map get repaired and get electrified for the duration of the power up, damaging any zombies that break a board. Kills zombies with 3 shocks on any wave. Note: Enraged zombies will instantly die due to their instant barrier destroying function, this can kill up to 72 zombies.

• In-game description: Time slows in proximity to zombies
  
• Functionality: When picked up, a turquoise aura is given to the player and slows down time up to 25% as zombies get closer to the player. Also moves the match timer to the middle and changes colour when time is slowed down. Reload speed stays the same giving you an advantage when time is slowed.