There are nine total chapters to complete in story mode. You will have to achieve set amount of score on each level to earn a gold medal.
After playing for a while, I know there will be certain levels that you try over and over again, but still don't rack up enough points for gold. Well, here are a couple of things that you should keep in mind while playing.
1. During fight scenes, always defeat your enemy by kicking them into different traps. You will earn 2,500 each time. Simply defeating an enemy or knocking them into the same trap again will only net you 500 points. If you run out of traps to use, play your guitar. You will be awarded 2,500 for each perfect hit with the guitar. You can hit a maximum of 3 enemies per guitar attack. Also, try knocking enemies into barrels, crates, and treasure chests for extra gold.
2. When playing through action sequences, (ex. running scenes) make sure to always use your sword and swipe anything in your way. There are barrels, vases, and crates that carry gold in them.
3. During balance, sneak, and pose sequences, try your best to achieve a perfect score. Only earning "great" or "nice" the whole time won't cut it when going for gold. Trust me, it will make all the difference. Certain running scenes will involve jumping and you will earn an extra 1000 for executing a perfect leap. This goes for chain jumping as well. (Must be 5 or more consecutive jumps.) Here's the break down of all the possible scores.
* Nice: 250 points
* Great: 500 points
* Perfect: 1,000 points