Upgrading Ships
From Galaxy Attack: Alien Shooter Wiki
Ships have Power (30 upgrades), Bullet Level (8 upgrades), Evolve (3 levels), and Rank (6 levels). Additionally, they have a Capacity for mounting Expert Items which can give each ship additional abilities.
Different upgrades cost different currencies. Earlier ships tend to upgrade exclusively using Gold. Higher level upgrades often cost Crystals. Bullet level additionally requires Evolve Stones to upgrade. Legendary, Lord and Tyrant also use Legendary Tokens to upgrade.
