Hexen 64 Cheats (Nintendo 64)

While playing, pause the game and press C-Up, C-Down, C-Left, C-Right. A CHEAT option will
appear on screen. Enter this menu, then quickly enter one of the codes below. 
  God Mode -- C-Left, C-Right, C-Down 
  Full Health -- C-Left, C-Up, C-Down, C-Down 
  Level Select -- C-Left, C-Left, C-Right, C-Right, C-Down, C-Up 
  Butcher -- C-Down, C-Up, C-Left, C-Left 
  No Clipping -- C-Up 20 times, C-Down 
  Collect Mode Cheats
  Enter these codes on the Collect Mode screen. See your manual for details. 

  All Artifacts -- C-Up, C-Right, C-Down, C-Up 
  All Keys -- C-Down, C-Up, C-Left, C-Right 
  All Puzzle Items -- C-Up, C-Left, C-Left, C-Left, C-Right, C-Down, C-Down 
  All Weapons -- C-Right, C-Up, C-Down, C-Down 
  Skip Part of the Hub
  At the core of the seven-portal hub there are three stairs that must be raised. After
you raise the first flight of stairs, walk halfway up them. You will see the other two
platforms that the other two staircases lead to. If you try hard enough, you can actually
jump to the smaller ledge, skipping a part of the hub!

This cheat works on All difficulties, including the Toughest difficulty.  It will only
work with inventory items only.  To do it, pick up an item, then quickly open up the
Hexen 64 Game Menu, Temporarily save the game, then reload it.  Whalla!  You will have
two of the same item.  You must time it right to get the same item twice.  It can be
repeated more than once until you need as much as you want.