I am really enjoying what Aksys is doing with the Bit.Trip series. First there was Beat, a throwback version of pong, and now there is Core, A completely different game, but with the same style as Beat.
Gameplay
Core's gameplay is completely different than Beat. Instead of focusing on motion control Core sticks to buttons only. This makes the game a lot more rhythm based than Beat because you have to push buttons in time with the music. Basically balls come from 4 different areas of the screen and to hit them you have to hold the direction on the d-pad and tap the "2" button in order to hit them. It might seem a little overwhelming at first but once you get use to the scheme of things the game becomes very satisfying. With enough practice it becomes second nature to hit all the stuff that's flying at you. Showing this game off to friends is awesome when you get good. They stare open mouthed because they think you are a game wizard. The difficulty ramps up pretty steep though. So you'll need to crunch in some hours learning the patterns to some tricky parts that seem impossible to get at first.
Pro tip: Sometimes you'll go into "challenge mode". In this mode, the directions are flipped making it extremely difficult to hit stuff coming at you. I found that the best way to handle this is turn the Wiimote around in your hand so that up actually is up from the way you are holding it. I know that sounds a little confusing, but you'll understand once you run into this.
Graphics
As far as visuals go, Core has the same beautiful retro style as Beat did. It's got the flat 8-bit theme on top and then the trippy surreal 3D environments in the background. There are four levels of visuals that can happen depending on how well you are doing. The more combos you get the crazier the visuals get. If you do poorly you go into a bland black and white mode.
Music
Core's 3 music tracks are amazing if you're a fan of Chiptune. The electronic beeps and bloops are very pleasing to the ear and go perfectly with the theme of the game.
P.S. if you dig the music to Core and Beat you should check out my favorite Chiptune musician CCivory. All his music is played on gameboys running a program called LSDJ.
When it's all said and done, Core is an awesome game for 6 bucks. The only shortcoming is the lack of online leaderboards, but that's not a big enough problem to keep you from not playing the game. This is a must buy title if you have a Wii.