Musical fans will really get into Amplitude. Modern songs are pulled apart, and the game is actually playing out the various parts of the song, in time.
Sometimes you don't realize just how much intricacy there is to a song until you start to listen to each track separately. Look at how the drums counterpoint the rhythm guitar. The voice interweaves perfectly. It's fascinating to play along with a given part, to see just how well it fits into the mix.
The downside of any game like this is always going to be the music mix. For example, Amplitude includes songs by Garbage, Quarashi, Chris Child, Run-DMC, The Baldwin Brothers, Weezer, and more. If these bands appeal to you, you'll have a blast. If you really hate these bands, you might enjoy the game, but it will madden you to have to listen to the songs over and over again.
I fell somewhere in the middle. I really enjoyed some songs, but just didn't like others. Luckily, I only had to win through a given song once before I could put it behind me :)
Graphics are reasonably good, but really the sound is key here. You barely notice the graphics that swirl around you as you focus on the song, the track markers, and the notes you're aiming to hit.
The game has great difficulty progressions so you could literally play this game for a year or more before you master some of the more difficult levels. If you have any interest at all in being a musician at all, those skills aren't wasted, either. Being able to master those complex rhythms are a real life skill that will serve you well.
Buy Amplitude from Amazon.com