[blanky!]

I'd have to say the 5th round had the most interesting files and songs, if not the hardest. You had a stacked songlist, from japanime D4 to memecore D7, and everything from D3-7 had some sort of nontrivial patterns (and even D1 with swing!). Adjacent rounds only had 1-2 charts that were interesting enough both song/file wise.