Here is how to enable the cheats on the Oni demo. It is both totally legal (doesn't use files from the beta) and it does not remove your save games.
This works with the Macintosh version Oni Demo ONLY, if you are using the PC version please go here (Thanx Bravehamster)

1. Make a backup of your persist.dat file in the Oni Demo folder. If you mess-up later you can fall back on the backup. If there is no persist.dat file there then you have not used the demo yet.
   
2. Get a low-level hex file editor. For the Mac I find that BrainHex (from http://www.psyber.com/~brainscn/brainhex.html) works well.
   
3. Open up persist.dat with the hex file editor.
   
4. Find the byte with the hex address of 47. It should have the value of 02.
   
5. To enable cheats, change the byte from 02 to 06.
   
6. Save it, and start up Oni demo.
   

If all went well, you should be able to use the cheat codes.
To enter the cheat code, while in game, hit F1 to go to the mission objectives screen and type in the code (listed below).
If successful it will tell you that in the hint text area.

If the Oni demo freezes up, then something went wrong. Restore the backup persist.dat and start over again if you want.
To disable cheats simply change 06 back to 02.

-The Binhqx

So here are the cheat codes:

• shapeshifter - Change Characters (with F8 key)
• liveforever - Invincibility
• touchofdeath - Omnipotence
• canttouchthis - Unstoppable
• fatloot - Fat Loot (Ammo+Health)
• glassworld - Glass Furniture
• winlevel - Instantly Win Level
• loselevel - Instantly Lose Level
• bighead - Big Head Mode
• minime - Mini Mode
• superammo - Super Ammo Mode
• reservoirdogs - Last Man Standing Mode (AIs fight with each other)
• roughjustice - Gatling Guns Mode
• chenille - Daodan Power Mode
• behemoth - Godzilla Mode
• elderrune - Regeneration
• moonshadow - Phase Cloak
• munitionfrenzy - Weapons Locker Created
• fistsoflegend - Fists Of Legend Mode
• killmequick - Ultra Mode
• carousel - Slow Motion Mode

Thanx:

• Dr.Qwerty/nop (who got me started in all of this)
• NHCowboy (who runs a great Carracho server)
• nrc (for getting the PC version to work)
• Bravehamster (for inspiring me to make this after seeing his web page)
• BrainScan Software (for BrainHex)
• Every one who gave me a helpful posting on the oni.bungie.org forum
• Bungie (For making Oni in the first place)
• Apple Computer (for making great hardware, software and hosting this page for free)

Disclaimer:
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