Open console (Tilde "~" for QWERTY keyboards or key "%" for AZERTY keyboard).
enter : Kingsoft 1
to activate cheat Codes.
Then you can use :
God 1 = God mode (God 0 to go back in normal mode)
FullLife = refill Max Health
fly 1 = Fly mode (useful to pass through walls or others obstacles) (fly 0 for normal mode again)
Reborn = ???