This is my first attempt at posting a wall, so I’d appreciate your feedback. Thoroughly enjoy this site!

Doubt you need much advice. The twenty line was clever . In part the grid was too special interest for my general knowledge but that's not really a fault - you will never please everyone. However a lot of gridders object to good answers being marked wrong. Be sure to accept for example movies as well as films. And keep up the good explanations.

Echo all of Toast's comments. Good stuff.

Agree with Toast's comments. Also your inclusion of at least 3 answers that could cross over into another line is a good feature. It might be better not to have 2 lines covering the same subject matter unless it is a specialist themed grid.

In my view, this grid falls into a well-defined category that we see a lot of here, and in that sense it's a pretty good example. However, I feel the whole concept misses the point.

First of all - and this is really just a minor quibble - the accuracy is not absolute. In general, the harder you make your grids the more precise you have to be in making the answers fit perfectly, and for example, X and Y are the mammalian sex chromosomes. That's not quite the same thing as gender, as some women are X, XXX, or even XY. I'd see that as a fine clue with "Mammalian Female" or similar, but you're not spot on here. I know the distinction is very minor, but in your position as quizmaster you need to be more than just 99% correct. (I've made this mistake several times.)

However, my second point is really the main issue: this knowledge is too abstruse. Fully seven out of the sixteen clues meant nothing to me even after seeing the answers. A quick google cut that to six (I was aware of the movie 21, but the title had slipped my mind), but that's still way too vague.

In my vision of a good grid, people who miss a group AND then miss the connection are at least kicking themselves when they see the answer. Or just maybe, at an extreme, interested to have learned or been shown something new.

Here you have a very easy Facebook group - nothing wrong with that - and then the wheels fall off. When the three minutes had ticked down and I saw the answers, my response was more "Huh" than the ideal "Ah!" of enlightenment. The clues are based on things I never knew, and now that you tell me I don't take any interest in learning them. "There was a film called Twelve, nobody really liked it and it sank without trace." Never knew that. Never really wanted to know it either.

Look at even the hardest walls the professionals put up on Only Connect - they may be fiendish in other ways, but not simply by calling on such obscure facts.

Perhaps you underestimate - or I overestimate - quite how special-interest this information is. In particular, are you a major cinephile? You have a lot of film clues in here that I found rather taxing. One trick you can use is to choose a name to post your puzzle under, so as to give users a clue as to the content.

In any case, please don't take my post as a deliberate attack on your grid. There are different definitions of what constitutes a good one, and I'm only writing this with respect to my thoughts, and because you asked for comments. Keep on gridding!

Appreciate the feedback James and, yes, I love my films so take your point that maybe not everyone is aware of Twelve which I maintain is better than its reviews although not a patch on the original book!