I reckon this isn't going to be updated within the foreseeable future, or do you plan on working on it at some point?
I had other things I wanted to do with it, but I'm focusing on writing a book at the moment.
Because the notes trigger using GameMaker's object collision, I had pictured other things moving on the screen that would interact with the "pointers". On the second hand, I am worried that I'm just piling on "stuff" instead of trying to work in some actual music theory. Then on the third hand, I think that if I try this I will make it worse - maybe DAM is better when it's doing wierd or ambient things.
I've made the source code available for anyone who wants to tinker around with it.