This is incredibly cool! Really well done. The entire experience with creating and listening to the tracks feels really good. I'm going to be using this for my next product demo video.

It's crazy how good the tracks sound.

One thing that would be nice is the ability (like some others have stated) to tweak the generated sound. For example, there might be a lull at 0:24 but given my video it would be best for the lull to be at 0:52 instead. Would be cool if the layers/pieces were moveable a bit to make it perfectly fit the content it's paired with.

Anyways, congratulations!