Ion Assault separates itself from both twin-stick shooters and other Asteroids rip offs with one key element, the way you fire bullets. Think of it this way, your bullets are scattered all around every level from the start. You can pull them into your ship and launch them back out. They then go flying into things or just around the level and you can pick them back up an infinite amount of times to reuse them.
This adds a new element of strategy because the longer you "charge up" (pull the ions into your ship) the stronger your shot will be because you'll have more ions collected to shoot out. However, you can't sit in the same area the whole time because you'll have collected the ions in that space and launched them to the other side. So you'll be forced to move around in order to be able to shoot, but you can also set yourself up if you launch a bunch of ions into one corner then go down there and start shooting from there. Or you can corner asteroids and when you shoot them the ions will ricochet back to you and you'll be able to collect them quickly again.
The games strategy doesn't end there, you'll need to figure out a lot for yourself, but I just wanted to give some examples since this is a bit of a different concept from other current twin-stick shooters. Of course there are also power-ups hidden in enemies and in asteroids to help you out. Power-ups come in two types, ones that take effect immediately (like shields to boost your defense) to ones that need activated (like rifts to funnel in and destroy enemies where dropped). These are nothing out of the ordinary, but they do look pretty awesome at least.
There are 4 levels in Ion Assault, each with a decent handful of stages and a big boss at the end. If you die, you'll simply have to restart the stage that you are on, but you'll lose all the points you have acquired up to that point. This is very generous of the developers as far as helping you be able to complete stages since the game gets fairly difficulut, however, it'll cause you to end up with some embarrassing low scores when you die on the bosses. You can always replay though to work your way up those leaderboards.
I never exactly felt at one with Ion Assault, there was something not quite perfect about the way it controlled. There are so many twin-stick shooters out there now, I feel like the developers should have spent a little extra time perfecting the feel. Collecting the ions also requires you to have the left trigger pulled in which hurt my finger a lot by the time I had finished my playing session. It'd be nice to have at least the ability to customize the controls or have an auto ion collector option. Using the keyboard is a joke (with all twin-stick shooters, not just Ion Assault), so I'm not even going to go into it, use a 360 controller if you're going to play this game.
Ion Assault also suffers from the fact that at the end of the day it's just a game where you destroy lifeless, slow moving, asteroids. Each level kind of goes through the same pattern. Some asteroids spawn, you start destroying them, some enemies spawn and space gets tight with all the little asteroid pieces then at the end it's just you and a few spread out small asteroid pieces you're left with finishing off. For as much as I think the bullet concept is an awesome idea, it also gets repetitive in that it's like having to charge up every single shot and getting stuck in a tight situation means you have no time to charge up and you have to just accept death.
I really do recommend this game though if you're into shooters of this family. It does enough different and has enough production quality that I don't think you'll be disappointed. It won't go into the hall of fame, but it's definitely a game I will remember and return to a few times.
Ion Assault was developed by Coreplay and is available for the PC for $9.99