Wow, what an odd mix of groups.

I found the grid itself quite easy to solve and two of the groups fairly easy (and satisfying) to link, but the explanations for the remaining two groups had me stumped, for wildly different reasons.

One of the connections is trivial to identify if you know a particular film (which I haven't seen). This was the weakest point of the puzzle for me and left me feeling a bit cheated.

The other connection I couldn't figure out is a couple of orders of magnitude more difficult than the remaining three, requiring very lateral thinking and extremely specialised knowledge. I didn't find it unfair -- just strangely at odds with the rest. And it taught me a few new words. Thanks!

All in all, not a bad grid, albeit a bizarre mix of almost trivially easy and fiendishly difficult puzzles.

Piglet,

Thank you so much for your incredible, specific and rightful reasons. You are nearly right about everything. I can assure you that I will improve myself. I will consider all of your recommendations.

The g group was clever but almost impossible to reverse engineer for the solver. I loved the word play, insightful. The other two relied on knowledge I don't have, but then so do many grids!