Available cheat codes unlock content or change story decisions as new options were unlocked. For anything else, you can simply use the renpy console.
KateSaint - It will alter the story so you helped Kate without taking advantage of her. This cheat will RESET Kate's story (includes pregnancy events).
KateMolestHelp - It will alter the story so you helped Kate after taking advantage of her. This cheat will RESET Kate's story (includes pregnancy events).
BellaRejected - It will alter the story so you rejected Isabella's advances. Even after her attempted seduction.
EarlyHalloween - unlocks all Halloween content (wallpaper, outfit)