If you like arcade games 2D old, do not miss Muramasa. Graphically, the game is gorgeous; I do not think I saw as beautiful on the Wii so far. The characters are real hand-drawn sprites, not 3D stuff based computer. The decorations are splendid, colorful, highly detailed (we almost forget that the Wii is not HD!). The gameplay is simple and effective, dynamic and nervous (note: personally I prefer the control to the Gamecube controller, but you can use the Wii Remote or Classic Controller). There is a touch of RPG, with character progression (gain XP and levels), management objects (food, various treatments, objects to protect themselves against this or that kind of attack), the different sabers one acquires during the game. As for the overall feel of the game, if you like Japan and / or mythology, you can only be happy. Most enemies are inspired by Japanese folklore (much like in Okami).
For me it is one of the best Wii games for those seeking something other than party game or casual gaming. A real good action game, in a style unfortunately abandoned by most developers the benefit of 3D (besides buying Muramasa helping you to recognize that there is always a demand for 2D games).