S.T.A.L.K.E.R.: Shadow Of Chernobyl (PC)

Enable unlimited running
Open the console via ^. Then type in g_always_run 1

To be able to run as long as you want without having to worry about stamina. To disable the code type in

g_always_run 0

Code - Effect

g_always_run 1 - Run without getting exhausted

Limited Edition passwords
Go to "Setup-bp" in your main S.T.A.L.K.E.R. dir. Chose your language and for Password # 1 input "pseudodog" to unlock the multiplayer map Pool as well as the UK and US military multiplayer skins. For Password # 2 input "snork" to unlock the multiplayer map Dark Valley as well as the French and German military multiplayer skins. These two codes are exclusive to the Limited Edition of S.T.A.L.K.E.R.

Password - Effect

snork - Multiplayer map Dark Valley, French and German military multiplayer skins.
pseudodog - Multiplayer map Pool, UK and US military multiplayer skins.