This one is very much along the lines of Decimation X with a couple of differences, the main one is that your ground based gun can alternate between the bottom and top of the screen while wiping out the enemies (who also flip round, albeit upon reaching the side of the screen while moving left/right).
It's not quite as bullet hell as Decimation, but is viewed closer in so it's as much a reaction test as it is weaving through bullets and you have to keep in mind what is heading down to the other side of the screen while you're flipping between them...
There are the usual powerups etc available, slow down the enemies. better guns etc.. and it looks lovely and plays fantastically well, adding a nice little twist to the usual Space Invaders formula, much like Decimation X did.
Very much worth a look also.. 240 points/£2/$3

Youtube Trailer
http://www.youtube.com/watch?v=uEaBHWmxtXo