Hello, I must begin saying that I didn't liked it. However, when the track finally builds up I got that retro feel I assume you where looking for. I think there is much work ahead to make this piece great, so I wont point out the details but the concepts that you should take in consideration next time. The first is the silence, music is made by the arrangement of sounds and silences, so to get the listener a break the mid range instruments ( melodic and harmonic instruments ) shall not be playing all the time, or at least not at the same level ( volume and intensity). which takes me to the second concept, low range instrument like bass or big drums are often the base of the son so, the brain is used to (and likes to) hear the melodies on top of a base or basic sound, in your case it takes too long to get there (but as I said before when it builds up it is awesome). Now, I actually don't know what the chord challenge was about, but I am sure that if you keep those things in mind you will get some kick ass beats. Hope I didn't get too heavy, and sorry if the english is not perfect, keep rocking!