Note: This procedure requires editing a game file; creating a backup copy of the file before proceeding is recommended. Using a text editor, edit the "player<0-5>" file in the game's saved game directory. You can edit the name, runes, and spells that you have.
Get the Crown Of Thorns power-up and the message "Destroy all enemies" will appear. Immediately go to the bottom left corner to get some random power-ups, runes, and spells.
Bosses hint: Pain Taught is the recommended spell to use against a Boss. Spread fired shots will converge on a single enemy and also gives the Poison status. Poison damage is based on the health of the enemy.
WildWind or Plague are the best spells for Non-Boss enemies. Plague has a decent spread and a fair rate-of-fire, and also inflicts Poison. WildWind makes little snaking "cracks" of ice which damage enemies. If it freezes an enemy, they will no longer be able to move or fire.