Actually having worked out a couple of the answers, I realise it's not quite what I thought - I was swayed by seeing 20 answers to work out, and there being 20 'things' which turned blue last week, if ...
As I mentioned elsewhere, I too found this site through Si's BBC Riddle, though your comment that none of your puzzles there are harder than round 1 ones here makes me slightly nervous - I thought som ...