Lumines is about as addictive as a game can get.
The minute you turn it on the catchy tunes will have you mezmerized. The gameplay is simple enough that anyone can enjoy the pleasures of eliminating blocks and creating musical fun.
You'll while away hours upon end challenging yourself to beat the clock on time trials, or the CPU to gain more skins; as well as taking on you family and friend in 2P VS.
The "skins" or musical backgrounds that are unlocked are plentiful, but I still felt there could have been more.
The only other thing is that Lumines really doesn't push the PSP hardware at all, but it shouldn't need to.
The game is fun and easy, and one of the best PSP games available right now. In fact, its the only game I've been playing on my PSP constantly since I bought the system.
If you like puzzle game, Lumines is a no-brainer. For everyone else, its a great distraction, and can spiral into hours of fun, if you're not watching your clock!