The first thing that I notice about the overall design, is that it looks a bit outdated. Even though it's very light with graphics, there should be more attention to the layout and typography. I would consider using a grid system to aid you with the design structure. It will help you organized text, images and divisions in an easy to place manner.
For example, I can notice that not all areas are properly aligned to the left. There could also use improvement on whitespace between the blocks of text. Also, I would use a better type face for your Headings. With today's technologies, you have the opportunity to use a better suited typeface for your heading titles, bold statements, etc. I would definitely stay away from Arial. The entire paragraph is bold which is unnecessary. You should use a normal font weight for the entire block of text.
The idea of having and animated navigation that you have to wait for is actually annoying for most people. It's fun to look at the first time. But having to wait for the rear hatch to open will make the user impatient and leave the site. Design wise, the rear hatch could use a little work on shadows. It looks like there was the default bevel and embossed used. It makes it appear as if the sides of the hatch are popping out, which should be flat. I would remove the shadows/ glare from the sides and reduce the depth of each rectangular space. Since I'm on the topic of the navigation, It's good that you included a <noscript> tag with an HTML version of the navigation. In case user has flash disabled.
Hope these few comments make sense and help
While I agree with the critique on age and simplicity (the site has actually been live for almost a couple of years now) much of what was mentioned were specifically requested by the client. Font - check, navigation - check.
It confirms much of what I felt when doing this site. I was really having a hard time balancing what the client wanted with what I thought would be decent design. I have since learned a lot both in terms of technical ability and managing client expectations. I am still learning as well and I thank you for the review. I will probably be doing another refresh on this site again within the next year (I know the client well) so I will take much of this and learn from it too.
An aside, they have received quite a bit of business from the site, so it can't be all bad, but I will strive to do better. Thanks again!