No particular reason 
. However, I have now changed the subtitle in CIU to mention U.C.O. 
Idea
No, they don’t.
No, because chips are the same as barriers – they don’t count.
Barriers were never meant to shoot. When I designed Shoot the Core, it was lacking in challenge, so I created the cannons to make it more difficult. It was a special case. In fact, until CIU, these barriers were hardwired to only shoot to the left.
Depending on your FPS and exactly where your projectile hit it, it is possible to speed it up, yes. It can’t be fixed.