I of the Dragon Cheats

Cheat Codes

To activate these cheats type the following codes while playing:
MAPGOUING - Show all map
FJKDKEARW - Unlimited respiration
YOUWIN - Win mission
TOPLSAN - Invulnerability

Invulnerability
You'll be changing a file so copy and pste old code for future refference. Now, in Windows, click 'Start', then 'Run', then type 'regedit' and press [Enter] to start the RegEdit utility. Find the following entry in the HEY_USERS section:
S-1-5-21-1177238915-746137067-854245398-1003
You'll see several folders there (Software, Primal, Dragon, Debug). Just click on the Debug folder and there will be key called 'Invulnerability'. Right-click on it and choose 'Modify'. You'll see that it's flagged to 0. What you want to do (to be invulnerable), is to set it to 1. After you do this, close down the Registry Editor, run the game and your dragon won't be able to recieve damage.

Hex Cheats

How to Modify Character Parameters
This information is ONLY for the demo version of IoD, it was not tested on the full version!
Most of the character parameters, namely: Fly speed, Fire power, Breath capacity, Mana inflow and Spell slots, are arranged into C-like structure that can be found in the save file. The params.txt file (download it from the link above) explains the layout of these values. To locate the structure, do the following:
1. Remember the Fly Speed parameter you currently have,
2. Convert the Fly Speed value to HEX format, and write it down with lower byte going first,
3. Save the game into file, find it on your disk and open it in a HEX editor,
4. Search file for bytes: FF FF FF FF <Fly Speed> 00 00 00 (I assume here that your Fly Speed is less than 256),
5. Modify known parameters as you need,
6. Write down the file and try it in the game.
Don't be greedy, too high numbers may render the game unstable!

How to Increase Life and Regeneration
Again, this information is ONLY for the demo version of IoD, it was not tested on the full version!
Unfortunately, the Life and Regeneration are not available directly from the HEX editor. Fortunately, though, the upgrade points are. They are located in the parameter structure with offset 0x0070 in relation to the 0xFFFFFFFFL signature. (That is, 7 times down arrow in Hiew after search.)
This is field for points. Under normal circumstances, you receive them after completing the next experience level. But now you can set the parameter manually to any amount you want. 0x3FFF worked fine for me. Then, you can load the game and distribute points for Life, Regeneration and even buy new spells.