Guitar Hero: Metallica marks Neversoft's second venture into the full band gaming genre. Metallica

The main appeal of this game is Metallica. You have a large selection of Metallic songs, detailed models of the band, and each Metallica song mo-capped by the band to bring you a realistic concert experience. All the songs performed by Metallica look fantastic. The polygonal metal legends look very just and stray from the caricature style of Guitar Hero. Each song performed by Metallica is a treat for the eyes especially when compared to watch the guests acts being performed which you can sometimes see entirely inappropriate actions being performed by the characters (for example, seeing the drummer drumming while there is not a audible drum track). After playing all the Metallica songs, the guest acts don't even seem worth playing due to those songs just not being as fun overall. I would've much rather see a game made entirely of Metallica songs.

The career progression and gameplay is what you'd expect from a Guitar Hero game. Progress through tiers and watch the resulting 30 second animations for each tier. (I think it's entirely possible to actually make a good narrative experience from each game and Guitar Hero should either go all out or just quit.) The progression is fine until you get to the last song in ever career, "The Thing That Should Not Be". It's as easy as the songs in the first tier of the career and is a huge source of anticlimax for players who like a good challenge. After, clearing the career mode you're most likely going to spend the rest of your time in the quickplay mode until you just stop playing. With the replay value of Rock Band 2 including a dynamic career mode and daily battles between other bands, Guitar Hero really needs to step it up in replayability.
The online gameplay is unchanged for the most part from World Tour except the omission of online band career. You have several quickplay and dueling modes to choose from, but some modes, like Band vs. Band, you can rarely find enough players searching in that certain mode to get a full 8-player party together. The ranking system used to compare players is the same from World Tour, which is based upon total money earned which I think is crap because anybody can get the highest rank with time. It should instead be a rank based upon star count or something similar that deals with skill instead of time spent playing the game.
Other added perks is an updated HUD that adds a star meter and clears up the screen a bit and "Metallifacts", for those people who love to fill their head with trivial, but cool knowledge.
Overall, while Guitar Hero: Metallica is fun, it just doesn't last. I consider waiting for a price drop before purchasing unless you're a hardcore fan.