Many acts in Sonic Rush contain hidden pathways that can lead to shortcuts, large ring caches, 1-Up monitors, or even Special Stage rings. These pathways are often not immediately obvious and require a keen eye and some experimentation to discover. Look for destructible blocks that can be broken with a Spin Dash (Sonic) or a Boost. Sometimes, a seemingly dead-end wall might actually be a hidden passage.
Vertical exploration is also key. Often, the highest routes in a level contain the most rewards and the fastest paths. Use springs, dash panels, and your character's unique abilities (Homing Attack chains, Burst Hover) to reach elevated platforms. Pay attention to the dual screens; a hidden path might begin on one screen and continue on the other. Don't be afraid to explore off the beaten path, even if it means sacrificing a little speed on your first few runs. Once you've found a shortcut, you can incorporate it into your S-Rank attempts. Replaying levels and trying different approaches is the best way to uncover all these secrets.