I'm not talking about the cannon pointing straight down, just the Y position of the ending point being lower than the starting position. When I did this, I was expecting for Daisy to be simply launched to the point normally, but the glitch made she point directly to the other way that she was supposed to go and stay in place (and still in cannon animation!).
Also, some unrelated cannon research: Setting the ? to 2 will make the char go much slower than normally.