Tap Shot will auto collect items in air, hold will auto collect ground gems.
Picking up items near where they drop will turn them white and make them worth much more.
If you point-blank enemies with the active shot (green or blue), you can shed small gems from them.
If you can get the multiplier above 9999, the rank will jump, and you will then shed large gems instead of small.
Thats just BL original. It took me a lot of practice just to get a stage 1 route that I was happy with.
Its great, because there are multiple levels of scoring. The game's difficulty is what you make of it (that mode at least)
I wouldn't call it simple though
I also need to put more time into cave. They only give back what you put into them. Pink Sweets is one astounding game.