I kind of tired after writing a semi-rant about FlashForward, so I'll keep it short.
It felt like the writers were grasping for straws with "Feet Don't Kill Me Now." Gus tap dancing is both funny and slightly cool. Lassiter joining in is equally cool. However, what was the relevance to the case? Lassiter is able to state the obvious, because tap dancing clears his mind. Over 5 minutes of the episode was spent on near-pointless tap dancing. It's funny, but like many things about Psych, completely irrelevant.
Since most of the episode was spent squabbling, the case was absurdly easy. In total, three suspects were introduced and it was clear who the murderer was from the beginning.
Score: 7.9/10