Talents
From Galaxy Attack: Alien Shooter Wiki
The Talent system has 1 main Talent and 12 Sub Talents. 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. A certain Talent rank requires a certain Experience Level.