Here is the full list of all 18 Ion Assault achievements.
Score exceeds 10,000,000 points (Survival).
Score exceeds 5,000,000 points (Campaign).
Score exceeds 3,000,000 points (Campaign).
Score exceeds 5,000,000 points (Survival).
Score exceeds 1,500,000 points (Campaign).
Score exceeds 2,500,000 points (Survival).
Score exceeds 1,000,000 points (Survival).
Completed the single player campaign.
Score exceeds 500,000 points (Survival).
Complete a whole sector without dying once.
Get two extra-lives with a single score upload.
Destroy seven asteroids at once.
Score exceeds 500,000 points (Campaign).
Complete a regular stage without collecting a single Power-Up.
Survive 3 stages in a row without losing a life.
Destroy five asteroids at once.
Finished a stage in less than 90 seconds.
Destroy 50 big asteroids in a single game.