Shadow the Hedgehog has always sounded interesting to me. It showed that Sega didn't necessarily take itself too seriously and was willing to have a bit of fun with their flagship license. I mean, c'mon. Giving a superfast hedgehog a gun seems kind of goofy, right? I figured that we'd get a fairly enjoyable game in the Sonic-style with a kicking sense of humor. It turns out that I was wrong of nearly every count.
The first thing you should know is that everything in Shadow the Hedgehog is played straight. Shadow's car-driving, gun-toting, good-or-evil antics are all for real and are all serious business. The general gist of the game is that Shadow's past is coming back to haunt him and he's also at a turning point for his future. He can either go good, evil, or stay neutral and do his own thing.
Each stage of the game that you play has three possible outcomes: Shadow dashes to the end and just grabs the Chaos Emerald, Shadow fulfills the evil objective and moves on, or Shadow fulfills the good objective. Each choice you make results in the stage progression branching off into a new direction. The choices are all up to you. if you want to go the dark route, pause the game and flick your objective option over to evil and listen to your on-screen helper seduce you over to the dark side. Want good? Do the same and enjoy your new sidekick. The helpers and sidekicks either help you fight or tell you what you need to do to win for their side. They'll switch randomly during the stage, which helps in the tug of war feeling that permeates the game. Will he or won't he? Is he evil or is he good? Is he something else? You have direct control over this.
This in and of itself is a great idea. It'd be nice to see more games reflect your choices during gameplay in this manner. There's a variety of endings, each of which is dependent on which path you ended up taking. It's great to see that we aren't just left with Good, Evil, and Neutral endings. Instead, we get shades of all of them. In this portion, Shadow the Hedgehog excels.
Where it doesn't excel, however, is basically in everything else. Shadow has some fairly serious control problems that wreck the whole experience. When he runs, Shadow looks kind of like he's ice-skating. It's a cool visual effect, but it's also eerily accurate. Shadow, nine times out of ten, does not do what you want him to do. He slips and he slides, which usually ends up with all your rings scattered around a stage or perhaps at the bottom of a very, very deep hole. The gunplay would be fun if you could actually properly aim the weapons, rather than pointing yourself in the general direction of an enemy and hoping that you're on track enough that you'll hit something. It's even better when you're trying to go strictly light and you tap the joystick wrong and kill some good guys by accident, thereby helping to fulfill the evil objective. How hard would it have been to work in the tried-and-true third person shooting gameplay from every other game ever into Shadow?
The weaponless action isn't any better. Shadow has a useless punch, and his homing attack isn't so much "homing" as it is "more likely to send you off the edge of a stage if you're even remotely off-center when you do it." The car driving bits are fairly inane and feel tacked-on. There are a few segments (particularly the theme park and digital world) that have little gimmick actions in them that are 1) no fun and 2) frustrating. I honestly don't understand why someone thought that shooting balloons out of the sky from a turret was a good idea, or that grinding along the edge of a digital world while the camera spazzes around you was a good idea.
The graphics for Shadow the Hedgehog are just serviceable. They aren't flashy or extremely detailed, but they are bright (sometimes incongruously so, as in the amusement park) and sufficient. The difference between the CG-animated cinemas and the actual gameplay is striking and, at the same time, disappointing. The cinemas are good enough that I wouldn't mind watching a Shadow cartoon using their visuals, but also so good that they take me out of the actual game. In comparison, the actual game looks under-detailed and drab. The animations in both the cinemas and in the game itself are good, but the real game could do with better textures. It just looks off and average.
You could make a very real case for Shadow the Hedgehog not being a Sonic game, gameplay-wise, and I'd wholly agree with you. It's something other, though there are a few nods to its Sonic origins. It's much more focused on objective-based action adventure shenanigans, for example, with less of an emphasis on the insane speed that's part and parcel of the Sonic series. However, that does not explain how we ended up with such a lackluster game. Shadow the Hedgehog has a couple good ideas that are ruined by sorry gameplay. What happened?