Bug Exploitation: "Infinite Saves"
As Carnby, when you leave the lobby of the manor, a cutscene begins and you meet Edenshaw. At the end of the cutscene he gives you a charm of saving. If you save immediately after the cutscene ends, then reload, the cutscene will begin again. Repeat. You will gain 4 saves each time.
Cheat mode enabling
To enable cheat mode in a game you should start it (ALONE4.EXE) with 'wizardmaster' or 'WIZARDMASTER' (no quotes) option in command line. Then when you enter the inventory, you will see the cheat menu there.
Missing one armed man
In the beginning. go to the left. After awhile, you will see a building. Enter it, and a man with one arm missing will be sitting inside. Talk to him and get the key from him. Go back out and keep going. After you start walking a short distance, you will hear gunshots. Turn around and go back in the building. The man will be missing.