Boom Boom Rocket is a fun, simple game with enough content to make it a worthwhile purchase.
The scoring is very simple. Each time a button is hit correctly and at the right time, it is scored from Perfect to "ok". Aside from giving points, with higher scores receiving more points, the scores are tallied into an accuracy rating which affects the grade you receive at the end. When a button is missed, no points are gained, and there is a penalty involved: the reduction of the bonus meter (explained later). Too many misses in a short amount of time can also result in a game over, so it is important to remain diligent in regards to hitting notes accurately. Misses also seem to decimate the grade received at the end, making avoiding them even more important.
The bonus meter is basically a score multiplier. At the start of the game, it is at x1, and there is no multiplication of score. After a small amount of successful hit notes, it will upgrade to x3, and then finally x4. When the meter maxes out at x4, the meter will glow, and by pressing the triggers a bonus run activates, which for a short time upgrades the multiplier to x16. When it ends, the multiplier returns to x1, and the process begins again. Scores of "Perfect" and "Awesome" will cause the meter to increase faster than "Good" and "Ok". The only penalty is for missing buttons, which results in a drop in the meter. If the meter drops below x1, the game ends. In the end, the Bonus meter really is just something to keep an eye on.
The game's music, while not terribly original, is of decent quality. Most songs are techno versions of classical music, one example being "1812 Overture" turned into "1812 Overdrive." Honestly, it is a bit cheesy, but not to the point where the TV needs to be muted. Some of it I actually consider decent, but that is just me. The game has ten songs by default, with five more available for purchase on the Xbox Live Marketplace.
Perhaps one of the most satisfying aspects of the game is the graphics. Each button, as shown flying up from the bottom appears like a firework does. When the button is successfully pressed, there is a firework explosion. During the bonus run, the explosions are larger and prettier, resulting in a highly satisfying experience. The background is a plain dark city, which is a tad disappointing. A bit more variety there would have been nice.
Overall, the game isn't too deep. Other than what has been mentioned, there are a few other modes, like endurance, where the song loops faster and faster each time through. The achievements fall into three categories: survival, performance, and completion. The survival achievements are awarded for lasting a set amount of time in endurance mode, for example surviving three laps on a medium song. The performance achievements involve scoring an "A" on an easy, medium, and hard song. The completion achievements fall into completing every song to a certain quality, or finishing ten songs. Leaderboards are available which let you know how you stack up against the world in many different categories.
Boom Boom Rocket is a unique, if not terribly original game. I recommend at least the trial version to anyone, which features a few songs to try out. From there, the full game costs ten dollars, which equates to 800 Microsoft points. In the end, it's a good, fun, simple game that at least deserves a try.