Press [CTRL] + [SHIFT] + [S] and when you hear a sound, type the desired code:

Code - Result:

instantprod - Instant Production
instantres - Instant Research
ai Toggle - AI on Own Player
upgradehero - Upgrade Hero
emergehero - Summon Hero Spell
cityspy - Spy on Enemy Cities
gold - Max Gold
mana - Max Mana
explore - Explore Whole Map
fog - Disable Fog
research - Research All Spells
win - Win Scenario
lose - Lose Scenario
freemove - Free Movement
towns - View All Towns
spells - Free Spells