the further you are from the knight things, the more damage their charge attacks will do. run at them if they see you, even if there's one or two other enemies nearby.
if you have something else to do for a few minutes, you can equip FION generator Z, and at the end of a level just leave the level complete screen open. It will continue creating boss killer missiles until you have 999 (Or you'll probably have like 20 million gold to just buy them by this point, so who cares).
It's obvious how you get 6000+ percent accuracy. you just shoot and destroy every single one of the shapes required to complete the stage in one shot and then die and submit
 "Where is cat?")
 "DPS Idle"){kind=icon}
 "Hack Slash Crawl")
 "Enigmata")
 "Micro Olympics"){kind=icon}
 "Heir")
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 "MARDEK RPG: Chapter 2")
 "BoomsticK")
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 "Monster Saga")
 "Globetrotter XL")
 "Zilch")
 "Run")
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 "Multitask")