These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
In earlier versions of XOP Black, unlocking Insane difficulty. It required you to 1cc the game on Very Hard. To those who don't know Shoot 'em Up slang, it means clearing the game on Very Hard without continuing.