Not gonna lie, they took ages. I can't put a time on them because I'd work on them in little 5 or 10 minute intervals, and often go back and change the things I'd done. But I did that for about a week and a half.
The thing was, I've been starting replays and not finishing them. Come up with something cool, and not be able to follow through. And these were basically my challenges to actually complete something.
That combined with the fact that I've hardly made any replays recently gave me enough incentive to finish.
Here's another. Larfen helped me out with it.
Hence the name.