Playing through this myself at the moment and it's great fun! Well worth a look, though I know there's a minor glut of games vying for attention - Bayonetta coming out on the same day unfortunately put this in the shade somewhat.
The combat is fairly simplistic, but allows you to expand your range of moves and with the gamut of additional weapons available, you can really mix things up. Exploration is great fun with some really fantastic looking levels. The puzzles range from the "oh that's a snap" to *checks GameFAQ* "oh darn - I should have guessed that!" Rarely frustrating and very rewarding when you get it on your own.
Definitely one to pick up.