Good job composing within this retro sound. What I liked most about it was the interplay of different melodic voices at times. It's somewhat difficult for me to identify the different sections, so in addition to changing the harmonic progression, I would suggest changing the arrangement during new sections too. For example, dropping out the bass and most of the percussion except hi hat for 4-8 bars. That way, the listener really feels it when you bring it back. Good work!