As the gameplay improves, so do the visuals. As ever, Retro has gone to town in creating imaginative, genuinely alien-looking environments packed with weird vegetation, strange ruined architecture and lovely atmospheric lighting. On the one hand, you could say that Corruption is solid proof that the Wii is never going to stand up to the 360 or PS3 when it comes to creating realistic detail, but on the other it also shows that slightly dated technology can still produce impressive work. Trust me: the screenshots you see here don't really do it justice. Once you're immersed in Retro's universe, you won't be worrying about the lack of normal-mapped textures or HDR lighting; you'll just be caught up in what you're seeing, what you're doing and where you're going next.
Here's another good thing: the first two Metroid Prime games were undeniably great, but they were also an acquired taste. This time, Retro seems to have hit a better balance between providing the challenge and depth the series is famous for while also entertaining the more casual player. Corruption is certainly slightly easier than the forbiddingly tough Metroid Prime 2: Echoes. Boss battles can still be a bit drawn out, but the patterns and weaknesses are generally quite easy to spot and the fights become less fearsome once you master the Phazon overdrive. Save points are more sensibly placed, and the game has a nice habit of checkpointing before potentially fatal sections.
Better still, there's less backtracking going on. Cunning mechanisms like a command to bring your ship to certain preset landing points help, as do some cool shortcuts that help reduce journey times back to the beginning of a section. Don't worry: if you're a Metroid veteran; you can still scan everything and read through masses of background detail on the history and inhabitants of the galaxy. However, you're just as welcome to ignore this stuff and blast on through.
All in all, then, we have a game that starts mediocre but keeps getting better and better. The more you play, the more the atmosphere grows, the more you want to see what's coming around the corner, and the more compelling the whole experience becomes. The music and sound effects effortlessly create that distinctive Metroid ambiance, and the whole package of visuals, plot and inventive gameplay works a treat. There are signs here that the Metroid Prime formula is getting a little tired, and the Prologue remains a disappointment, but when you come away from Corruption you'll remember it as one of the strongest games on the Wii, and one of the most immersive game experiences you'll have this year.
Don't let a bumpy start spoil another great entry in the Metroid canon. The first-person gameplay and the Wii controls are a marriage made in heaven, and the game gets better and more immersive the longer it goes on.