Firstly, in order to activate an ingame (clickable) Cheat Menu one must add an extra line "Debug.EnableCheats = True" (Without quotes) into a file "config.cfg" located in:

C:\Users\[YOUR USERNAME HERE]\AppData\Roaming\Kalypso Media\Dungeons3\config.cfg

Sometimes the game will automatically set the TRUE value into NULL, so we may want to set this file to be read-only.

Then you start a game and click tilde ` or ~ button (above "TAB", left of "1") and we will see a big clickable menu of cheat options.

Code	Effect
AddEvil	Sets evil points to 10000.
AddGold	Sets gold to 10000.
AddMana	Sets mana to 10000.
FillWorkshop	If you've built a workshop, it will fill it with stacks of boxes (trap/door materials)
FinishAllResearch	Researches all possible research projects. This will give you all available rooms, traps and level up your heroes.
SetCreaturesInvulnerable	All your fighters and heroes are now immortal and deal huge damage.
SpawnHero	Spawns a generic "enemy" hero on the viewed location.
SpawnSuperCreature	Summons a super soldier (usually an Ork) with humongous HP and damage.