Fail, and Isis will be pissed and you’ll be forced to try again. Succeed and you'll collect coins, jewels and the approval of an Egyptian deity as you continue to the next level, where the balls will have a different path, more colors or a faster rate of descent.
By the way, yes: it's essentially the same as the Xbox 360/PC game Zuma, and as the DS game Magnetica, and probably also some other clones we don't remember. The only difference is that you're hucking balls straight up from the bottom of the screen instead of spitting them every which way from the center of it. We don't actually know which variation came first, but this one was apparently invented in ancient Egypt, so we reckon its chances are as good as those of any version.
Anyhow, power-up stones deliver the game's big twist by temporarily reversing or stopping the approaching spheres or by destroying a few with explosive fire, zappy lighting or a magical scarab with an extreme case of the munchies. Besides helping to clear the level, they also provide an occasional flashy punch to the game’s stoic hieroglyphs.