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