Type "zaphod" while playing the game.
Dev console will open.
Type your cheat and hit enter.
Console will close.
Open the console with the tilde key ("~") at any time after this.

Effect                       Code

god mode                   - god
heal group                 - healall
keep same char for attacks - hold campaign
kills target               - kill
load game                  - load [savegamename]
no dialogs anymore         - toggle important
save game                  - save [savegamename]
set character level        - set charlevel x
set hero                   - set hero [ENTITYNAME]
set level                  - set level X
set time scale             - set timescale [X]
teleport to character      - goto [ENTITYNAME]