Ok, yes. The indestructible barriers were interfering. Fixed in v.86 
Bug
No, not easily.
I tested it and I was able to get it. It’s very hard though, because it’s all one long chain of 45 enemies, and one mistake loses the Bonus.
Ugh, confirmed. On the list to fix.
Because your contact list is not refreshing in real-time (you need to exit the screen and re-enter it)
Changed in v.86 Idea
It does, but since all barriers are part of the same chain, you must not destroy any of them. This is really only practically possible if you spawn behind the barriers.
What do you mean? Don’t custom backgrounds work retro & anniversary?
Only the ending difficulty (including skill boost) matters. There is also a penalty for “short” (<50% of maximum length) missions. Score plays no part.
Known, but not worth fixing.
Well, this is the type of mistake you only make once, so… no.
Dammit, thanks.
Sadly, this is sometimes possible, due to the way the scrolling direction and zoom change abruptly.
I currently have bigger chicks to fry. Sorry.