Given that you're not selling individual tracks (that I can see), it seems odd to me that there'd be any option to download tracks one by one.
EDIT: It gets worse. It seems they haven't heard of authentication, either.
You can buy music without creating an account (that's a good thing), but they haven't mastered the art of providing a download link that no-one can guess. Instead, they say: "Please note you MUST access this page using the same computer and browser you placed the purchase with." WTF?
1. What if I can't download now and need to try later on a different computer? What if something goes wrong? What if I close my browser and the cookie that gives me access is deleted?
2. There's nothing in the Digital FAQ about dealing with such problems.
3. One troubleshooting step in the FAQ says: "If you cannot download the test file try using a different type of web browser." But you can't! It won't work.
One last complaint about the individual track downloads: it's hard to tell which ones you've already downloaded, since there's no numbering and visited links aren't shown in a different colour.
EDIT2: Even more astounding, one of the albums had no MP3 tags. What a pain. The other was okay, though.