This is for creating a maximum bonus combo in Raiden Fighters Jet,
which is earned by stringing quick shot combos which are quick kills on larger enemies as they enter the screen.
This is most easily achieved on the sky type level (sim 35?), I believe you need x9 but I lost track as that level gets a bit hectic there.
this is seemingly not earned by the floating point pickups, so don't worry about those.