Think Killer 7 in 3rd person, better graphics, mixed with GTA, God of War and Zelda.
Graphics are very nice and kind of anime. It definetly one of the most stylish games on Wii with all the menu screens with a great 8-bit look. If you like the strange, you will love this.
Gameplay is very hack and slash. It does a mix of buttons and Wii control. It work very well. It can get repetitve but in a good way. The same moves manage to thrill one more time. The sandbox part of the game is also very fun. The minigames are fun and you can also buy new things like clothes and beam katana upgrades. You also get a cool bike.
Music is very nice. The tunes are strange just like the overall feel of the game. Also has some nice 8-bit sound effects.
Overall it is one of the best games on Wii. Hardcore gamers will love it.