I have this game for PSN as well. On the surface it looks like a new school version of the arcade classic Ateroids. It is a simple mouse and arrow key game with a few special weapons. The objective of each stage is simple.... blow up all of the asteroids. There is an option to use the X-Box 360 controller, but there is no menu support for the controller which leads you having to use the mouse anyway. To top that off, the targeting is literally rotating the ship instead of just aiming at something.
Ion Assault has a few twists that make the experience both better and worse. The improvements to the experience are simple, variety of enemies and boss fights in the story mode. These are the only good things about the game that add to the old Asteroids formula without taking away.
Now for the negatives, lets start with the fact that you need to absorb ions to shoot. This means you need to hold down your mouse button and fly around the single screen stage to collect ions. The more ions you have, the stronger your shot will be from your space ship. Its not just enough to hold it down, but having to collect the ions seems like a chore. Your ion blaster doesn't feel impactful at all even when fully charged with a screen full of ions.
Another downside is having these ions EVERYWHERE means the screen is covered in blue and for the most part the enemies are blue... a brighter blue, but a blue nevertheless. It just makes it more difficult to see. This is a game about precision, having to shoot in a direction with your mouse, all while piloting around a single screen. To make things worse, if you knock the screen border, your ship will bounce off and most likely hit something and make you die.
This is not a fun game, but it is a challenging one. Every level / stage feels exactly the same as the previous. Destroy asteroids. Shoot them and they split in pieces which then need to be shot again and again until they are no more. Eventually your screen will just be full of enemies, with your weapon too weak to kill anything. If I could shoot without having to collect ions, then it would feel better.
I cannot even justify this game for $2 even if the Steam version is superior to the PSN version in ways that seem inconsequential. Oh and to top it off, Beat Hazard is just a lot more fun and you can see what you're even doing without having to charge a beam.