Good Grid.

Nice one.

Typed 'river' and got 'incorrect'.

I typed rivers and got "correct". It is sometimes tricky to cover all the possibilities when adding the answers, but one tip that is mentioned each time is to use short versions, so "comed" will cover both comedian and comedy. If H had put "river" instead of "rivers" it would have accepted both. Before complaining about the answers though, its worth creating a few grids of your own to see how tricky it is. I like to think that I cover all bases with my answers, but I still get complaints when a "correct" answer is marked wrong.