Go to the end of a level and find the goal ring, don't quite go in it yet. What you want to do is get a run up, and then press start and restart level just before you touch the goal ring. As the level starts up, you should hear a goal ring sound. This means you've done it correctly. If not, you haven't correctly timed it. On the level's results, it should have the time 00:00:00 when you view it in the world map/entrance stage. This helps with the achievements that require you to beat the level under a certain time limit (such as blue meteor which requires you to beat Windmill Isle Day Act 2 in under 2:35 or Speeding Ticket which requires you to beat Arid Sands Day Act 1 in under 2:50 which can be a heavy pain. P.S. I'm not sure if this glitch works with Night Stages as I haven't been able to get it to work with Sonic the Werehog.