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