They just had to drag Walken and Shannon into this, didn't they? Kangaroo Jack is the story of... You know what, no. This movie tries to have too much story for a movie that uses a CGI kangaroo this much. It's insensitive, weird and not super well made, even though I weirdly thought the CGI kangaroo actually looks decent for a 2003 movie.
In short, this is not a good movie. Is generic, not that funny, doesn't hold up to modern standards and yet I weirdly have a good time with it. This is probably a nostalgia thing so I can't recommend anyone watch this if they've never seen it. Even if you have seen it, don't go out of your way for it but if it happens to be on it might be worth a smile or two.