To call this game "Tetris on a sphere" would be a bit disingenuous. It's far, far more complicated than that. Tetris merely requires you to place falling pieces such that they create solid, dissolving rows and thus abate, if temporarily, the peril of becoming overwhelmed by the steady stream of burdens in what I can only assume is a clever metaphor for adulthood. Globulous, on the other hand, has a clear goal: clear out layers of the sphere and reach the prize inside.
When you're creating a game, there are a few key things you need to include: a good atmosphere (be it an intriguing story or just some wildly immersive effects), good gameplay mechanics, and a good hook. What's going to grab the users' attention? Well, for Gears and Guts, all three of those requirements can be summed up with "driving cars into zombies." Oh, and did I mention there's a sweet soundtrack to go along with it?