Destructoid - http://www.destructoid.com/review-ro...z-233739.phtml
Completing a stage comes with three kinds of awards based on player performance: Stars, Cred, and Coins. Stars and Cred are experience systems. The former are awarded based on total score and range from 1-5, or gold stars (which, for the purposes of scoring, counts as a sixth star). Cred accumulates in small quantities, pooled from performance on individual instruments and earning it unlocks new power-ups. Coins are an in-game currency system used to then purchase unlocked power-ups before stages begin, awarded based on the number of stars earned and the overall difficulty of a stage.
It's up to the player to find combinations which work well for individual songs as well as suit their own skill and style. They absolutely make the game, in terms of fun factor and strategic depth. The purple note power-ups in particular add a welcome bit of chaos, keeping the player constantly on the lookout for opportunities to score and giving some hope that it's possible to squeeze a few more points out of a stage through a combination of skill and sheer good fortune.
All of these elements combine to create an addictive, fast-paced, and challenging game. It also, by virtue of its mechanics, has a most interesting balance in terms of compensating for less skilled players while putting the screws to the hardcore at the same time. The range of acceptable timing for hitting notes feels rather broad, which is great for the newcomer who may struggle for a little bit. That same range is downright punishing once you have the hang of managing multiple lanes, as (for the purposes of accuracy) the game determines that if you can hit a note, you must hit the note. It's very easy to hop to a neighboring track, expecting to slide between notes, and be penalized for missing one which is just barely playable. This can make all the difference when it comes to maintaining Blitz Mode or amassing big points with the Jackpot Overdrive power-up, making risky moves all the more exciting to attempt.
Rock Band Blitz can be a bit of an isolating experience, especially in comparison to other Harmonix titles (such as Rock Band or Dance Central) which encourage an infectiously fun, party atmosphere. With those games, a significant amount of enjoyment can be derived from simply being with people while they play but there's nothing interesting to watch (on-screen or off) when Blitz is being played. The game has too many nuances to be quickly explained to a casual observer and the scrolling background of Rock City isn't really exciting. Other people in the room are probably going to be bored.
Between the trash talking and head-to-head nature, Score Wars are easily the most fun you'll have playing Blitz. The problem is that they're also only really functional with Rock Band World integration and this marks the greatest shortcoming found in Blitz. Without enabling this feature, the only way to initiate Score Wars is through the "Recommended" tab found in the game's menus, which will helpfully suggest a person and song to engage, but doesn't offer any means of specifying an individual player or song. People who opt out of using Facebook will likely be frustrated by these limitations.
Rock Band Blitz isn't going to change the world, with its appeal as a game likely limited to a niche market of dedicated rhythm game players, but it is fantastically fun to play and features considerable complexity