Not too shabby; crop off the plain-colored stripes around the edges and this is a pretty good representation. In fact it's almost certainly better than anything Prokudin-Gorskii himself got—can you imagine the precision required to line up the light beams from the projector he used? These negatives yield enormously better results than any other color photography method of the period that I know of (it boggles my mind that these are almost 100 years old, one could almost imagine they were taken yesterday).
This is probably good enough for web work, but before trying anything close to print quality it's a good idea to go through the procedures in the second lesson, for reasons hinted at below.
This does bear out the theory that it was done with a single-lens camera (three lenses would have been my initial guess, but maybe I'm just crazy). I'm guessing then that the partitioning of the color information was done internally with mirrors.
While this method of camera construction was undoubtedly less expensive than using three lenses (which would have been costly to grind, especially given the degree of desired uniformity), it introduces other problems that will be addressed in later tutorials. In fact, you may see the problem already (try scrolling further and further up).