Open Regedit (start menu, click on 'run' and type in 'regedit') go to HKEY_LOCAL_MACHINE/Software/Computer Artworks/The Thing/1.0 (or whatever version you have) then create new string values called:
DoInGameLoadSave (save wherever you want)
FullWeaponEquip (all weapons)
NPCInvulnerable (all your team members invulnerable)
After this right click on each value and choose 'modify' and change each values number to '1'.
The in game load option is buggy, so is best not to use that, simply load from the main menu
Contributed By: dunknash.