Part of why it's risky to use Cerberus deck is that you either need Cerberus or magic cards that can destroy Toon World early in the duel. Since this deck is built differently than to use on other LD or other CPUs, it also has more defensive cards that aren't spell cards, this is for protection so that the toon Monsters won't attack or attack directly.
It is recommended to finish the duel getting over 5000 damage if it gets dangerous with the toon monsters.
[Sorcery Conduit] Can be used each time your Life Points decrase by 1800. In the Draw Phase, instead of doing a normal draw, draw a random Spellcaster-Type monster.
It's important to remember that you shouldn't use Twister freely. If there is another set card beside Toon World then it can either be Judgement of Anubis or Michizure. If you don't have Cerberus on the field yet, then you can use Twister, but if you do, then you will need Trap Jammer set the turn before, so that it can be used in case Pegasus activates either Judgement or Michizure.
If you don't have Cerberus in your starting hand, then you will need to get hit and take at least 1800 damage in order to activate the skill. If 1 monster attack can already activate it for you then it's better to destroy the Toon World as soon as you can to prevent taking more damage.
Watch Your LP
If your LP is very low, you will need to heal up quickly since Pegasus can summon his Toon Cannon Soldier, which doesn't require Toon World spell, and he can set toon monsters down to be used as tribute to deal damage. The card itself can also be tributed, which can deal a lot of damage to you quickly in a turn.
The Finishing Blow
The spells in the deck might not be enough to reach over 9999 damage, so it's better to reach the "over 5000 damage" score. Either by getting more than 5000 attack and use Stop Defense then Riryoku, or getting more than 6000 attack and use Shooting Star Bow - Ceal. Remember to get to 0 cards left for extra points post duel.
This deck is really risky and you have to plan ahead but for people who joined after Ultimate Rising, its still possible to use this deck. To counter Toon World I use De-spell x2, Spell Purification x2 and at least 1 Malfunction. Other than that almost any other spell card is good.