Overall i think you put a lot of effort in this . Although because you change pace so often it may be difficult to apprehend the melody .
Try to hold the melody for about 4 loops before you transition .
dude...you cant hold the melody for soo long in drum and bass because
it gets boring,you must do a vast dynamic range of sounds to hold the crowd
in head all the time,this is drum and bass mate.
Please contact me if you would like to use this in a project. We can discuss the details.