Probably worth mentioning if the shifts can be in the past or only in progress/future.
Nice Kata!

Ahah thanks! But what I meant is I actually used the exact same solution from the easy one, but yea maybe I just did it right from the first try :o

Good Kata, but doesn't feel especially harder than the "easy" one :)

I agree. It is not clear if all the dead ants' bits will still remain (i.e. will have moved in the string) or if some of them could be incomplete.

I agree. It is not clear exactly what the output should look like until you see the tests failing.