This book is good fun - other people have complained that some of the things are undoable, and that's the only drawback. You can have good fun, though, trying to figure out ways to get round them, or interpret them a little more 'loosely' so that you can complete the book!
I haven't really found myself going out of my way to do any of the things listed; I guess that's another drawback - there was nothing that made me go 'oh, I must do that!'.
It's a fun book though, and especially if you let yourself bend the rules a little, you can have a lot of fun!