As in the other HoMM 3 game press [Tab] and type in the code:

 nwcphisherprice         New - but funky - colors
 nwclotsofguns           You get all war machines
 nwctrinity              Fill empty slots with 5 archangels
 nwcagents               Fill empty slots with 10 black knights
 nwcfollowthewhiterabbit Maximize luck
 nwcmorpheus             Maximize morale
 nwcwhatisthematrix      Reveal world map
 nwcignoranceisbliss     Hide the map again
 nwcneo                  Gain a level
 nwcnebuchadnezzar       No borders for movement
 nwcoracle               Reveal puzzle map
 nwctheconstruct         Gain 100,000 gold and 100 of each resource
 nwcthereisnospoon       Gain 999 mana and all spells
 nwczion                 Gain all buildings
 nwcbluepill             Lose game
 nwcredpill              Win game

 There is a secret cheat menu in the game. Start the game with a parameter
 /nwcgrail and press [F4]. In the windowed mode you have a new option
 Cheat Menu.