This is Jeff C's result of hard work with this hard game. Looks good. (Better than Morimoto's run, which was here earlier.)
Selected comments from the author:
This 4th attempt (10:15) is 3 seconds faster than the last one and has better form. Theoretically it is probably possible to save a few more seconds, but I don't think I will try any more unless I hear of a way to get under 10 minutes.
I changed level 2 a bit and it resulted in a significantly better time for that area. This is also the area where I found the other obscurity. The trick was like Castlevania's floor skipping trick by getting hit. A bat can elevate the knight up one floor, but there was no opportunity to use it in the game, unfortunately.