Now, the thing to remember first and foremost, is that Radiant Silvergun was never released in North America, meaning you'll have to import it. Of course a great number of us already have, so it's not unlikely that you'll run into a copy on Ebay, or something. However, with that being said, you HAVE to import it.
Many people who read my Bangai-O review felt that I held some distaste for the development company who made it -Treasure. But that couldn't actually be further from the truth. It's because of great games like Radiant Silvergun (the unofficial prequel to Ikaruga, also by Treasure), which made me so disappointed by Bangai-O.
You'll have noticed the large fanfare that accompanies any mention of Ikaruga around the Defunct Games site, and that excitement is certainly not unfounded, but to be honest Radiant Silvergun deserves equal acclaim.
While Ikaruga has more style, with it's black and white shots, and the player swapping colours to collect them and shoot them, Radiant Silvergun has another unique element going for it.
You see, in your average top-down shooter, you'll fly about shooting enemies who drop power-ups, and change your weapon into one of about three or four different guns. But in Radiant Silvergun, you have all the different guns you can fire at all times. You have your three different guns (plus a beam-sword), and 3 different weapons based on combining the three existing ones (by pressing them together, or using the pre-set buttons for them).
This creates a much more complicated and interesting game play element, as you're switching between weapons on the fly, and trying to determine which weapon would be most effective against which boss, or which stage of each boss.
But to add to that, by combo-ing your kills by shooting only certain colour bad guys and not missing you level up whatever weapon you use to do it, which inherently increases the power of the combined attacks. Also, once powered up, the weapons stay powered up. When you get a game over, you're also given the option to save. You'll start at the beginning next time, but your weapons will still be powered up. Which is a good thing, since you'll have to power your weapons up a lot, and earn a bunch of lives and continues in order to defeat the final boss.
Furthermore on the issue of powering up your weapons, the R button controls the aforementioned 'beam-sword', which you can use to do a quick swipe, or hold out in front of you by holding the button down. But most importantly, you can use it to collect certain pink-coloured shots fired at you ala Ikaruga, which powers up a meter. The full meter allows you to perform a devastating full-screen attack that looks very impressive, and does a fair amount of damage to everything that isn't you.
Of course, being a Treasure shooter, the bad guys are VERY numerous, and the action is incredibly fast paced. Hope you're good at dodging shots, but if your not, it's okay - you will be.
The last thing to mention is the animated cut-scenes. The game opens up with a very long, and very neat anime scene that introduces the plot (of course it's in Japanese, so I have NO IDEA what they're saying), and once you complete the game there's another long anime cut scene, which you'll understand even if you don't speak Japanese (like me).