Could've been really good, but the end result isn't worth playing.
This game follows its titular character, Shadow the Hedgehog, an artificially created hedgehog whose speed rivals that of Sonic the Hedgehog. He was introduced in Sonic Adventure 2 as 'the ultimate life-form' and this game begins with Shadow suffering from amnesia after the events of Adventure 2. The only things that he remembers are his name and a gruesome memory of the death of a mysterious girl named Maria. As he ponders about who he really is, the world is suddenly invaded by an alien race known as the Black Arms. Their leader, Doom's Eye, appears before Shadow telling him of an 'old' agreement they had to have Shadow collect the Chaos Emeralds for him. Realizing that the Emeralds could help him regain his memory, Shadow sets out to find them as he soon has to decide whether to be a hero and save the world from this new threat or be a villain and take part in destroying the world.
Shadow the Hedgehog controls just like the other Sonic games. Shadow is moved using the control stick and can move at lightning fast speeds. After going into a jump by pressing the A button, you can press that button again to have Shadow go into a homing attack that can lock onto enemies. It also comes in handy when traversing across large pits where a slip-up will have Shadow plummeting to his doom. Holding down the X button will have Shadow go into a rolling spin, and when the button is released, he will roll forward in the direction he's facing. This can be used to get under low barriers, though you really only need to just press the X button to slide through them. Pressing the B button will have Shadow perform an attack but while moving through the level, Shadow will come across weapons that he can use like guns or swords which are much more powerful. These are picked up just by walking over them, but if you need to switch weapons, just press the X button near a new weapon to pick it up. Running out of ammo? Just walk over another weapon identical to yours to get more.
The main aspect of the gameplay revolves around the choices that Shadow makes along his journey. Each level offers at least two different missions that Shadow can complete, usually either one where he aids the Black Arms in taking over the world or a mission where he aids heroes like Sonic, Tails, or Knuckles against the Black Arms. Some areas offer three missions, and these third missions consist of Shadow aiding no one and just collecting the Chaos Emeralds. This are referred to as 'Neutral' missions. Completing each mission will take you to different stages depending on what path you chose and in the end, the overall path you take determines the ending you get out of 10 possible endings. The whole 'Path' style of gameplay is the best part of the game because it offers much re-playability, especially considering that there are only about six stages you go through each time before facing the final boss, making it a fairly short game after going through it once.
But Shadow the Hedgehog has a lot of problems that hinder it from being a good game. The first problem lies within its gameplay, mainly in regarding to the type of missions that you complete throughout the game. Nearly every mission in this game consists of Shadow performing a task where he has to do an objective a certain amount of times, whether it's taking out a bunch of enemies or finding a bunch of items. That means that you're going to have to stop every time you see a enemy, take him out, and then continue on your way until you find another one. Why is this a problem? This is not what these Sonic games are all about. They're about speeding through the levels as quick as you can and in the end, I took my time through these levels. Unless you're a master at this game, I guarantee you that it will take you quite a while to earn 'A' rankings in every single stage. If you miss an enemy, you're going to have to go to a checkpoint and warp to another area of a level (which believe me, you might have to do a lot) in order to find the last few enemies you need to take out. When that happens, it takes forever to complete a level.
The controls are also rather clunky. Really, this isn't really surprising considering how these 3-D Sonic games have gone. They always do take some getting used to, but this is really not one of those times. I also feel like the addition of guns feel rather out of place for a Sonic game. This and the frequent use of words like 'Damn' or 'Hell' are the main reasons why this game is rated E10+ and really it just comes off as intentionally hilarious just to hear Shadow and the other characters swear every few minutes, though it gets annoying after a while.
All in all, Shadow the Hedgehog is not the worst Sonic game ever but I have to admit, it's near that level because some of the steps that this game takes in its gameplay don't work out in its favor. Even though this game is rather short when going through it one time, its multiple paths and endings do offer much re-playability. But would you be willing to go through a game where you can't speed through levels like you would in any other Sonic game and have to check every part of the level for something that you need to beat it? Odds are you'll only play through Story Mode once, and don't get your hopes up for Multiplayer. As with most Sonic games, this mode doesn't really offer much. If the creators did a better job at handling the overall gameplay, then this would've been a much better game. But for what we got, I can only recommend it as a rental.