The melody is reall cool, the frequency spectrum appears to be a mess, I mean some frequencies are barely hearable. The sidechain feels really weird, it's too long and not large enough imo. The drums samples are cool. The 808 is really quiet, try distortion on it. 5:58 is pretty long, some parts are a bit repetitive. GarageBand is good to start, but if you enjoy making music, I recommend you to switch to a proper DAW.
Keep it up,

~ Ahurac