It was a very iterative / derivative process getting to where I am with this game play mechanic. First I was making a geometry wars like twin stick shooter, but then I played
Liblade, which is essentially a side-scrolling twin stick hack n' slash.
Really fun—I highly recommend checking out the demo. The secret to having a platformer with right stick analog control is having the R1 button be the jump. Ape Escape did the same thing. So I tried turning my project into a side-scrolling twin stick shooter.
Finally, one day, on a whim, I randomly added gravity to the bullets. Shooting the bullets and watching them fall in an arc reminded me of water—so I turned the bullets into water and realized how much like Sunshine it ended up—one of my favorite games—so obviously you gotta add a boost—which of course leads to a much more intuitive and simple, but also very powerful control scheme. I am really pleased with it.