Oh how I love the Raiden series. I have fond memories of playing Raiden at the arcades, then on my Atari Jaguar and later Raiden Project on Playstation which include Raiden 1 and 2. I recently purchased Raiden Fighters Aces and enjoyed it, but these games weren't really sequels per sey. In comes Raiden IV which I really enjoyed. True to the Raiden series, Raiden IV can be quite challenging. At times there's so much coming at you that it could be hard to react to everything, but I've found that playting through the different included modes a few times seemed to make the games a bit easier.