I wouldn't say the review is unprofessional, it just seemed like the reviewer came into the game with a preconceived notion and played it just to confirm what he already felt.
His review clearly misses the point, and it really misses the mark in terms of score. He bares discusses the gameplay and makes the case that you can just flail around and win (not true). You might be able to get by for a little while like that, but you will eventually miss enough and lose. The soundtrack thus far is actually very good, and I find it strange that he criticizes it when it is more or less what you would find in a DDR game.
This visuals are pretty much not important and the shallow visualizer in the background provides just enough background noise to not be distracting but still give the game some personality. I don't even understand the jabs at the shallow motion stuff, the game is impressively good at recognizing gestures and at least on the medium difficulty the game is challenging and fun.
Like I said before, the guy seems to have used his review to justify his predetermined hate of the game. Sure you look like an idiot playing it (he must've been too cool for it), but it is a ton of fun while you are playing it. Someone needs to fill him in that he doesn't look any cooler rocking out with his plastic guitar or drumset.
All in all, crap review and it doesn't even begin to describe any aspects of the game. Stuff like this should be an embarrassment to IGN. It is clearly obvious to me that they barely put 5 minutes into the game, and really phoned it in.
FYI, I'm leaning towards giving this game an 8 because it does have some flaws but is ultimately very enjoyable, and can make for a great complement to something like Wii Fit for upper body work out.