How do you complete the mansion of madness on timesplitters

First you go into the mansion, then you just follow the paths made by unlocked doors.
If you get stuck somewhere, either you are not suppose to be there, or you need to do something in the area before you go deeper.
(Note: when you get to "princess", dont look up at her and save your bullets. Near the hole there is an eye, shoot that twice with a shot gun and she's down!)