The Talent system has 1 main Talent (shown in the middle of the display) and 12 Sub Talents. The main talent affects your starting Bullet Level. The other talents are Stone Drop, Super Time, Shield Time, Bomb Damage, Spaceship Damage, Alien's Move Speed, Alien's Bullet Speed, Quest Items Drop, Lucky Ship, Drone Lifetime, Drone Damage and Evolve Time.
In order to upgrade the Main Talent, players have to fully upgrade all the Sub Talents. The Main Talent has 4 levels. Each Sub Talent has 12 levels. To upgrade the Main Talent to levels 1, 2, 3 and 4, all Sub Talents need to be upgraded to at least levels 3, 6, 9 and 12 respectively.
Gold is used to upgrade Sub Talents. Each talent upgrade costs more than the last. The full cost breakdown to upgrade is as follows:
Your Talent Level is displayed at the top of the Talents screen. The first number is your current Talent Level. The second is the maximum you are currently able to upgrade to. Each Talent rank upgrade requires a certain Experience Level. You can see your progress between each experience level after a PvP match on the Victory/Defeat screen. The large number in the circle is your current Experience Level. The progress around that number is how far you are until the next Level.
In this screenshot, the player is currently on Talent Level 118, and is just over 1/4 of the way to level 119.