Press ~ or ^ to display the console window and type @Password( "Panzerklein" ) to enable cheat mode. Now, you can use the following codes at the console window:
Level select: SetIGlobalVar( "Cheat.Enable.Chapters", 1 )
Level skip: @Win( 0 )
God mode: @God( 0,1 )
God mode with one-hit kills: @God( 0,2 )
Take enemy units: @ChangePlayer( [number],0 )