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