In our upcoming game Velocity, you are rewarded for three different play styles – Speed, Destruction and Survivors Rescued. Each aspect awards an XP value, which allows you to progress in the game.
Levels are therefore designed to challenge you in all three aspects, and can be played a number of ways to earn XP.
For example, someone who is good at shooting enemies can progress into the game without having to rescue many survivors or do it particularly quickly, but at some point they’re going to come across a level that is locked, and they will need to revisit earlier levels to balance their performance across the other aspects to unlock further levels.

Earn Perfect Triple-Stripe Gold Medals by being... Perfect.
Speed and Survivors are the two critical aspects of a level that you can fail a mission on, so the medals reflect how well you performed on those critical aspects: Bronze, Silver or Gold for Speed, and One, Two or Three stripes for number of Survivors rescued.
So, you can earn a Single-Stripe Bronze Medal if you suck, and a Triple-Stripe Gold Medal if you rock.
The Perfect Triple-Stripe Gold Medal is awarded when you have mastered all three aspects in the level; you can collect every survivor, you can take down all the hostiles, and you can do it bloody quickly – all in one attempt.
When you’ve reached this level of excellence, you clearly rule at that level, and deserve such a pretty medal for your efforts

"I totally rule, that perfect medal is mine!"