Unlock Cheat Mode
To unlock the following cheats you must first enable the developer's console under the 'Key Settings' section of the 'Advanced Settings' menu during gameplay by entering 'sv_cheats 1' without the quotes into the console.

Unlock God Mode:
God

Unlock Infinite Arrows:
Arrows_unlimited 1

Spawn an Item:
Give (item)

No Clipping:
Noclip