Maximum number of Norns
To alter the maximum number of norns your world will support you have to change the value for the registry key: HKEY_LOCAL_MACHINE\Software\CyberLife Technology\Creatures 2\1.0\MaxNorns
It is currently set to 16. This number also affects when the hatchery will shut down, once the population reaches two-thirds of the maximum poulation it will close.
To alter the game mode you should change the value for the registry key: HKEY_CURRENT_USER\Software\CyberLife Technology\Creatures 2\1.0\Privileges
It is by default set to 'user' but if changed to 'blueberry4$' then cheat mode will be enabled. When in cheat mode you have access to a new menu which has some testing options within it. While playing in cheat mode the game will not autosave - so make sure you save before exiting if you have creatures within your world.
Revitalise your Eggs
To revitalise any eggs you have in the eggs folder you should change the registry key: HKEY_CURRENT_USER\Software\CyberLife Technology\Creatures 2\Hatchery\1.0\Eggstra
Each egg you have placed into the world will have it's name listed in this key and a value of 'omelette'. Remove that entry to get the egg available for use again.
Convert your Sprites
There are 2 types of video cards as far as 16bit graphics are concerned, one that uses 5 bits for each of Red, Green and Blue and another that uses 5 bits for Red and Blue but 6 bits for Green. These are often referred to as 5-5-5 and 5-6-5 respectively.
Creatures 2 is shipped with all the sprites in 5-6-5 format and will convert them the first time the game starts if you have a 5-5-5 card. There is a way to trigger the game to check your card and convert any sprites that need to be changed - this can be useful if you aquire a lot of graphics from someone who uses a different type of card.
To cause Creatures 2 to convert any sprite files in the wrong format you can change the registry key:
HKEY_LOCAL_MACHINE\Software\CyberLife Technology\Creatures 2\1.0\Display Type
to a value of 0 (zero). Then, next time Creatures 2 starts up, it will convert any sprites as needed.