Monster cheats
In the temple is some holy water. You can sacrifice various monsters in its murky depths by trying the following:

Imps	Sacrifice these fellas and you'll find they'll be cheaper to create in future
A fly and a spider	Create a warlock 
2 beetles	Complete current manufacturing 
A beetle and a spider	Create a dark mistress
3 spiders	Create a bile demon 
A vampire	All monsters will be afflicted with disease
2 bile demons	Turn all monsters into chickens
A horned reaper	All monsters become angry!
A dark mistress, bile demon and a troll	Get the horned reaper
2 flies	Complete current research 
A ghost	All your chickens die!


Don't sacrifice
Sacrifice the undead or chickens and the gods will become very angry. So don't do it unless you want some trouble.

Horny nutter
The horned reaper can go a bit nuts. If this happens, chill him out by dropping money on him. 

Secret levels
You can find access to secret worlds on levels 8, 9, 14, 15 and 17. Keep your eyes open.

Moon levels
Did you know that there are secret levels that appear during certain moon phases? So check your diary for lunar occurrences. The chances are something new is going to happen.

More levels
To play the multi-player maps against the computer, go into the DOS prompt, switch to the Dungeon Keeper directory and start the game by typing the following: keeper95 -1player, or keeper -1player.