Knockin' is the 11th release from the musical Monstercat duo KUURO. It features their first attempt at Halftime DnB, and is one of the only four known tracks in that genre to be released on the label as a whole.
The Japanese letters appearing in the cover art represent the name of tracks KUURO have previously released. (アーモン = Aamon, 強盗 = Bandit, 野蛮なやつ = Savage, 前兆 = Omen, 闇 = Dark).
"Aamon" is translated as "アアモン" in the picture, but this is grammatically wrong as the same katakana letters are not used continuously (Corrected translation for Aamon: "アーモン" or ”アモン").