This was impressive indeed. It was written entirely in  assembly(not using the DC katana library or directX) to get the most out of the Dreamcast. 
Also it was years and years before they were able to crack it to be able to copy the discs and by which time both the Dreamcast and Bleem were long dead. The author has a post on a gaming forums about a few years back.
Pretty cool stuff given the tiny size of the team that worked on this and the financial resources available to them. Sony eventually sued them into the ground.