A solid addition to anyone's Sonic or Wii collection.
One slight thing that always grated on me was how much harder it is to get Sonic to go backwards than forwards - if you so much as tilted the Wiimote forwards a little bit, off Sonic would rocket forwards, cancelling out the careful backing up you had been doing. I realize that Sonic brooks no time-wasting, but for the sake of players, they could have made the reverse gear just a tad more useable.
The game contains an interesting experience-level system, which gamers would be much more accustomed to see in an RPG, not in an action/adventure game. Nonetheless, it works well enough. As Sonic gains levels, he acquires skill points, which can be used to equip skills, as well as increases his maximum ring count and soul gauge, the latter of which can be used to unleash awesome powers when full. The developers were nice enough to provide you with four sets of saved skill sets, to enable easy switching between sets depending on what you need to do in a certain level. The usefulness of this becomes more and more apparent as the game goes on, as you'll only be able to equip about half of the skills you have near the end of the game. I personally made use of these by creating an "all-around" ring, a "pure speed" ring, and a "battle" ring; other sets would certainly have been possible, as well.
I must admit that the story in the game was a bit lacking, although, given that it was a Sonic game, that's to be expected - they never particularly are very deep (nor are they intended to be). Still, I gotta dock them points for this anyway, as I felt that it could have been much more than what it was. The story itself isn't really that much of the point, though (80% of the game isn't even advancing the storyline much), so having a boring one isn't that bad.
The part where the game assigns you a bronze, silver, or gold medal based on your performance in each level was a very smart move on Sega's part - it makes it so that gamers can feel that not only do they need to complete each stage, but that they also need to complete each stage WELL, which will always encourage gamers to stretch out the game to its full extent, thereby increasing its replay value by a huge amount. Smart move by Sega - but hey, it works, and I, being a competitive sort, enjoy trying to go for those elusive gold medals.
The game was a very beautiful one to look at - Sonic was definitely in tip-top form. The levels were all designed very well, and had a very interesting feel to each of them. Since each level has you do well over a dozen missions in them by the time you've complete the game 100%, you start to get a real feel for each level and its intricacies (which is very important if you want to ever get those gold medals!). I can't really think of anything to say about the graphics other than "well done".
The background music was pretty good, although the "rock and roll electric guitar 24/7" thing can kind of get a little boring after a while if you play the game too long. The voice actors... well, they could be better, and were kind of corny at times, but the number of video game voice actors that aren't that way are very, very few and far between, and they got the job done in an okay enough fashion.
The game was, to be honest, a little short in strict terms of its gameplay start-to-end credits time. It's only been a weekend, and I've already completed it (although I still have about one-third of the missions still to go, and from what I've seen, they seem very hard). So I have to knock off a little bit from the value score as a result. It still is a great addition to any gamer's game collection, but whether you get your full money's worth depends on what you're looking for. If you want an in-depth, immersive game with an expansive plot that will take you days and days to complete, this is not that game.
All in all, Sonic and the Secret Rings has its definite flaws, such as the slightly awkward controls or the shallow plotline, but they're far overshadowed by the fact that, darn it, this game is just plain fun to play. And when it comes right down to it, that's what Sonic is all about.