Visually the game isn't anything that special. The game looks about as good as an old Xbox game. Given that the Wii is capable of a lot more, this is almost shameful. The audio isn't much better. Crypto and Pox are both voiced by different actors. The delivery of the lines is just not as good as it had been in the first two games. The music tries to capture some of the vibe of the '70s, but it's pretty much a hit and miss affair. Some of it works and is catchy, some of it sort of falls flat. The sound effects on the other hand do their job pretty well.
On the whole, Destroy All Humans: Big Willy Unleashed isn't a terrible game. It does tend to get a bit repetitive after a while. Thankfully the game is pretty short, and most people should be able to blow through it in less than a night. Destroy All Humans: Big Willy Unleashed is a pretty decent rental. It's worth trying out but it's hard to recommend it at full price.