I think first off the bat, I notice your music player. While I’m ok with the song, I know having autoplay music can be a huge turn off for a lot of tumblrites. I would suggest not having it on autoplay just to not deter more people from your blog. I think where autoplay songs are alright are the live previews. So I think if you want to display songs there it would be less uninviting there.
That aside I think you have a very unique style. I love the style of your theme blog and I think the color choice is great. The organization is pretty much perfect. You have all the links that people would be interested to getting to and it’s accessible. It’s lovely and unique and shows your own personal style. It’s so hard because the critique for your theme isn’t really critique so much as personal preference/nitpickyness…
Instead of having your page navigation all the way at the bottom I would maybe put it under where you have your theme links on the left? Just that way people don’t have to keep scrolling all the way to the bottom to navigate through your pages. The other thing is just a nitpicky thing. Since I feel like all your links are concentrated towards the left, it took me a while to realize that your index/ask/etc. links were over on the right. So, to sort of balance it out I think maybe just make your title banner at the top longer to stretch to where your sidebar is or just switch where your main links and other links are.
You can basically ignore those things though because it’s more personal preference than anything. Your theme is pretty flawless side from the auto playing music and there’s not much I think needs to be changed about it. You have a lot of themes and again it’s just a testament that you know what you’re doing so I’m not sure this review provides much help.