There is no forum topic for this game other than this submission topic. So I'm just going to post here about a possible improvement I found:
After going to the SUPER STAGE (black screen), and then moving through the next room, you will land in this room:
Instead of moving through this room, you can apparently press "right" and then on the next frame "left" to go to the next room. (The problem was that moving into a "next room tile" with leftward speed would bring up the long SUPERSTAGE black screen, whereas rightward speed would not. By using the input I described above, you can make the game believe that you have rightward speed while moving into the tile from the right.) With some better luck manipulation it might also be possible to get an even faster "plate room" (the room where you fly on a plate).