Cheat Mode:
Start the game with the "wizardmaster" command line parameter to unlock a cheat option at the inventory screen. Here's an easy way of doing this: Create a Shortcut to the game on your Desktop. Right click on it, go to properties. You will see something like: c:\****\****exe. Just add wizardmaster to the end of this command line and then click Apply. Now start the game.

Infinite Saves:
When leaving the manor's lobby as Carnby, a FMV sequence will play when you meet Edenshaw. In the sequence, he will give you a charm of saving. Immediately save the game when the FMV sequence completes. Keep saving the game repeatedly to get four save uses each time.