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