Wonder Balloons and Riryoku are the most op broken cards in the game. Riryoku is a general purpose power up that works with every monster and is pure benefit for its user, you can win the duel in one move because its the exact the same thing as attacking directly by simply using spell card with no additional cost. As for the Balloons if you draw them in your opening hand you win the duel 9/10 times, All you have to do is to discard all of your cards and no enemy monster can ever harm you. Eventually your opponent loses due to deck out. The only way to counter these cards is to fill your deck with magic jammers, tornados and de-spells, which is not fun at all, ruining your deck with all these anti-spells just to prevent two cards.