I was bored, so I slapped this together in a couple of hours. The song is "Higher Than A Skyscraper" by Hybrid. If you liked this, you may want to check out my Two Steps From Harkinian YTPMV series.
Well, people like RobGBA (who's a better YTPMVer than me) heard all these little inaccuracies in them, like little off timing bits, not so well-chosen samples, stuff like that which you probably didn't hear. I may be able to make YTPMVs (and there aren't many people who can), but I don't know if I'm "really good" as you say. I'm glad you liked it, though. :)
You mean The King & Friends Randomness? It's not really Rosen-inspired, but... The only problem is that they take a while to make, and I already have a few other projects I plan to do first. It's not a big priority at the moment.
