For Metallica fans, this game is incredible. For everyone else, it's a decent spinoff in the Guitar Hero series that improves a few things.
Guitar Hero: Metallica is the second band-specific spinoff in Activision's Guitar Hero series after last year's Guitar Hero: Aerosmith. Unlike Aerosmith, Metallica's Guitar Hero game features the full band experience. However, it falls into the same trap as the Aerosmith release: it has a narrow set list that doesn't contain much more than Metallica and similar music. It does have an ace in the hole though. It has better special features and even adds some small things to improve the Guitar Hero band experience.
The set list, all master recordings, contains 31 Metallica songs and 21 songs by other bands that are some of Metallica's personal favorites and influences. The other bands included range from Queen and Lynyrd Skynyrd to Slayer and Mercyful Fate. Also, along with the current members of Metallica, King Diamond from Mercyful Fate and Lemmy from Motörhead make appearances as playable characters. Sadly, not all the songs are available from the start, and they cannot be transferred to Guitar Hero: World Tour. There is also no way to access any downloadable content that you may have amassed in World Tour.
The game plays almost identically to last fall's World Tour, with a few new additions. The biggest one is the added drum difficulty, Expert +, which uses a second kick pedal (purchased separately). Expert + is only featured on a few songs, but that is better than having the harder difficulty level shoehorned into every song.
A star counter has also been added to the in-game display to measure the band's overall song rating from zero to five stars while you play. There is also now a rock meter for each member of the band, which shows how players are doing in the song and helps address the problem of players failing and ending the song, which I brought up in my World Tour review. In addition, the game features a way to view the lyrics outside of the song, a lot of bonus videos featuring the titular band, and Metallifacts, which are music videos for each song that feature the in-game character models and are littered with pop-up facts.
The music studio introduced in Guitar Hero: World Tour is also in the game in its full glory. Added to the studio are more Metallica-influenced sounds, which don't really change that much besides giving the player a way to focus more on creating Metallica-sounding songs.
Overall, how much you will like Guitar Hero: Metallica is proportional to how much of a Metallica fan you are. It's a great package for fans of the band and die-hard fans of the Guitar Hero series starved for new music. If you're not that into Metallica and their genre of music, you're better off waiting for another Guitar Hero or Rock Band game to come along featuring music you like.