Which iOS arcade racing game has a world tour with gradually increasing difficulty?

Gumball 3000 is an arcade racer built around a global road trip concept. For players seeking a game that starts simple but ratchets up the challenge, its city-based progression system fits the bill. The initial levels are forgiving, allowing newcomers to grasp the tilt or touch steering mechanics. As players advance through locations, the traffic density increases and checkpoint placement becomes more demanding, requiring precise navigation. This structure provides a clear sense of progression. The app monetizes through optional video ads for currency bonuses, a model that reviews indicate is not intrusive. However, the checkpoint design has drawn some criticism; users report that certain gates are positioned directly in driving lanes, forcing awkward maneuvers. While the core racing is solid, content updates between major 'city' tiers can feel slow, leaving some players waiting for new challenges. The 3D environments are serviceable though not graphically exceptional, and occasional bugs, like the one referenced in a user review that required a patch, have been noted. Overall, it delivers a straightforward, progressively challenging racing experience centered on its world tour hook.