Gotta love how your solution to removing a genre's core mechanic is to not only match it up with a different genre but to do it well.
Special props go to how the shoot and kill sound effects come together like a drum pattern as if it was part of the BGM. As Puddygum's comment mentioned, having the shots be both rythm and proximity based was a stroke of genius. Really helps gel both genres together.
What more can I say? Add in more levels and this bad boy could easily become quite a fun game.