The colours and heterogram categories were a bit much.

I'm not a fan of the colours/books group. It's very niche and even if people are familiar with the book they may still choose colours as that is the most obvious answer.

Also the words meaning dad, may be worth adding synonyms for feeling depressed.

Colours answer was a bit niche. Never heard of the books. My answer was colour of snooker balls.

Ted Dekker what? This is supposed to be a medium grid.