seems to be down at the moment, but it is most likely a technical issue that has yet to be addressed.
Unfortunately the site downtime also took out the requirements & diagnostics pages. Here
is a Google cache of the download/requirements page, which may help you resolve dependency issues (scroll down to the Hardware Requirements section). If you meet all of the prerequisites and the game still crashes then check this cache
for further diagnostic steps to follow.
You mentioned in IRC that you are running Windows XP. Latest in-dev builds (any W1xx) no longer support that operating system, but I believe
that W71 (the latest version you'd have access to if you haven't purchased yet) still should run on XP. If you are able to get W71 running and still wish to purchase, you would be strongly advised to upgrade your operating system so that you could enjoy future versions of Blockade Runner.
In any case, the game is indeed still being worked on. The devs have been rewriting the game's engine so the latest public build is getting a bit long in the tooth in the meantime.