Geometry Wars is fun, but it can get boring after playing the same thing over and over.
Here is where the game falls short for me. It has only one game mode, with the exception of the evolved and retro settings, which are basically the same thing and do not change gameplay. They have great fast paced shooting, but after playing the same game mode many times it gets mind numbingly repetitive.
Graphics are amazing for an Xbox Live Arcade game. The visuals are really nice and flow well with the game's atmosphere.
Sound is great too. You have a fast paced techno track playing that doesn't get boring and is fun to listen to.
Geometry Wars is worth a buy, and you may find that you like it a lot more than I did. After all, this is just one opinion.