First of all I want to clarify that this was all a team effort and want to publicly thank the people at the community cheat hunt thread for their invaluable help in bringing everyone these cheats:

• MelonLad
  
• Itchy_Tacos
  
• Oswald
  
• F0st1n4t0r
  
• Fr0st Zer0
  
• bnanahome9000

You can copy and paste these directly into the text box.
Ordered by their menu appearance:

Quarter Existence 3 - Unlocks boomer shooter shader

Central - Unlocks Infinite Ammo, the variant where you still have to reload.

Mango Mayhem - Unlocks big jumping

999FPS - Unlocks zoomies, ultra movement speed for the player

Meow Meow - Unlocks looooong slide cheat

ILIKETHICCSTORNKSANDICANNOTLIE - Unlocks Aliens Everywhere mode

Size Queen - Unlocks Big Head mode

Alens wer here - Unlocks low gravity

Glock - Unlocks the Almost God cheat

gr8supergunm8 – Unlocks fukken fast guns, you fire and reload extremely fast.

555-420-6969 - Unlocks Hyper Speed, basically Turbo Mode where everything goes twice as fast.

Microwave - Unlocks sparta physics

pee and poo - Unlocks all guns, two complete columns of them.

Spliff and Drift - unlocks all consumables, an entire column of options