Here is the full list of all 26 Ionball 2: Ionstorm achievements.
Get Multiball modifier with Fireball modifier in main mode
Max out Laser upgrade in main mode
Max out Machine Gun upgrade in main mode
Max out Railgun upgrade in main mode
Max out Rocket upgrade in main mode
Earn 4,000,000 score points in main mode
Max out tesla upgrade in main mode
Use Kamikaze upgrade in main mode
Get Multiball modifier with Machine Gun upgrade in main mode
Max out EMP upgrade in main mode
Get Multiball modifier with Tesla upgrade in main mode
Kill Leviathan in main mode
Get a perfect round in main mode
Max out EXP Magnet upgrade in main mode
Complete a level in main mode
Destroy a droid with Ionball upgrade in main mode
Gain Fireball modifier in main mode
Get Multiball modifier in main mode
Get x5 Perfect Round bonus in main mode
Get revived by Second Chance upgrade in main mode
Kill Guardian Boss in main mode
End a level with 3 balls in play in main mode
Kill Blades Boss in main mode
Max out ball damage in main mode
Max out shields in main mode
Max out bat length in main mode