Cheat mode
Hold R + L + Y + Down for three seconds to toggle the following cheats on and off.

God mode
Press R(3), L(3), R, L, Y, R.

Auto-win
Press R(2), L(3), R(2), Y(3).

Level select
Press Y(3), L, R, L(2), R, L, R(2), L, R, L(2), R, L, R, L(2), R, L(2), R, L, R(2), Y(3) to unlock the "Bling" profile with all levels unlocked.

Fog of war
Press R, L, R(2), L(2), Y(2), L, R.

Decrease speed by 50%
Press L(5), Y(4), R.

Increase speed by 200%
Press R(5), L, Y, R(3).

Additional 100 Gold
Press L, R(4), L, Y, L(3).

Additional 100 souls
Press R, L(4), R, Y, R(3).

1000 Gold and Souls
Press R(2), L, R(2), Y(3), L(2).

Level 1: Easy health
When controlling a Stone Ogre and your health is low without any Hellfire to eat, scoop up one of those annoying sheep. This is a good strategy for retreats, and the sheep will give more health than Hellfires.

Easy win
When playing a mission with two or three Clans, you can defeat oncoming enemies rapidly by creating only ranged Goblins such as Archers, Hunters, Mortars, Savages, Mages etc. When the enemy is attacking, line your Clans of 10 into a line and wait for the enemy to approach. When in range, your Goblins will fire a volley or two and mow down most of the enemy without sustaining much damage.

Using cheats for practice
Use the three saved game files as follows. Enable the "God mode" code on the first file; the "1000 Gold and Souls" code on the second file; and no codes on the third file. You can use the first two files to learn how to proceed through the game, then actually do so with the third file.