Hmmm, I don't believe you need scripts for any of those (Not custom scripts anyway).
1) The bottle: Simply have your bottle entity as dynamic (Go into the bottle's properties and change the "Static Mode" field to "No")
2) The zombie: I believe there are already zombie scripts, one of which I can recall is in Nickydude's guide. Just search for Zombie, lol.
3) The darkness: I don't believe you want darkness, but instead the lack of light. Simply set your level's ambient light to something low, like 10. Then have a light within your room away from the area that you want to be dark.
Hope that helped you out some.
The one and only,
~PlystirE~
Dammit, Jim! I'm a programmer not a graphic designer!!!