Here is the full list of all 20 Stellar Warrior achievements.
Finish Level 06 - Alien Core at Master Levels
Destroy 50000 enemies.
Finish Level 05 - Volcano at Master Levels
Finish Level 04 - junglyard at Master Levels
Finish Level 03 - Ridding Hot at Master Levels
Finish Level 02 - Water World at Master Levels
Destroy 10000 enemies.
Finish Level 01 - Star Chase at Master Levels
Collect 500 power-ups.
Finish Level 06 - Alien Core
Finish Level 05 - Volcano
Destroy 1000 enemies.
Finish Level 04 - Junglyard
Finish Level 03 - Ridding Hot
Collect 20 power-ups.
Collect 100 power-ups.
Finish Level 02 - Water World
Finish Level 01 - Star Chase
Collect 5 power-ups.
Destroy 100 enemies.