Shadow The Hedgehog is a giant failure for Sega. Sonic is going downhill, it seems.
Gameplay: The gameplay is fairly bad. The game isn't very fast, but it is alright. For the first time in Sonic's history, you are able to wield guns and drive vehicles. The latter doesn't make much sense, because isn't Shadow supposed to be one of the fastest things alive? Well, anyway, the levels are sometimes huge, but that doesn't make up for the crappy gameplay. Also, the few levels where you are inside a level could possibly give a kid a seizure. The multiplayer is bad, too, so don't play it.
Story: You play as Shadow while he tries to unveil the secrets of his past. The game is multi-pathed, so if you choose a specific mission, it will change the course of the game. You have to play every level to unveil the true ending. Not much more can be said. You meet up with other Sonic characters that will travel with you while you do there mission.
Graphics: I think that this is a Dreamcast Game. No, seriously. It looks like a Dreamcast game. Only the fmv sequences look even moderately like a Playstation 2 game. There are also many graphical glitches that occur. The framerate on the Ps2 is uneven. Some parts appear to be in slow motion.
Voice Acting: Starting with this game, the sonic X crew do the voices of Sonic. Ughn. Only a few people even sound moderately okay, and those characters aren't very major. Thankfully, the Ps2 version allows you to listen to the ever better Japanese voices.
Music: The game supports the normal Sonic music that you here, as well as a few new, somewhat better pieces. General stuff here, people.
Fun: This game is only fun if...
1. You're a die hard sonic fan who must have every game. (Somewhat me)
2. You play bad games to see if they really are bad. (More me)
3. Torture is getting old.
Overall: If Shadow the Hedgehog was from a different series, this game could have been passable. But the fact that this game is one of the sources of the downfall of Sonic makes it bad. The few things that are okay with this game are overshadowed by the problems.