Zeus on the Loose adds new cards, with new powers, a lot more interaction, and a Zeus statue.
Let me summarize the root game, as it were, according to Pagat, who classifies 99 as an “adding game”: “These are…games, in which the values of the cards are added together as they played in a single pile, the object being to avoid taking the total above the target score (98, 99, 100 respecively).”
So, you see, if your card has the power of, for example, reversing the digits (one of my favorites), you can make the card total, which is currently at, for example, 93, become 39, don’t you see.
Interesting. Fun, even. But it’s the “lot more interaction” that earned Zeus on the Loose it’s Major FUN for Kids award. It would have to be. Because the added functionality and the significantly silly images of male and female Greek gods, and even the cool little Zeus statue cannot be compared in fun value to the Stealing Zeus rules.
You see, to win, you must be the Holder of the Zeus. To be the Holder of the Zeus, you must steal it from a player who is currently Zeus-Holder. O, you steal quite openly, there is no deception involved. Merely the experience of complete, if temporary, vindication. And then it gets stolen from you. And you can’t win without it. And then you do a “Same Number Sneak” (see the rules), and steal it back. And, well, it’s like a whole nother game, as it were. Like 99, sure. And Straw. But a whole new level of fun.