Maybe the Engineers could have been more like this and Shaw was right "We were so Wrong!"

"pranking civilizations"....that's a scream avensis.  

Pretend extinction, raining cake balls, have toads speak English for an hour (and they hold strong toad-centric opinions), etc...Yes, that would have to be the best part of being a powerful alien avensis.  

I would schedule a fake moon-sized meteor coming in quarterly that disappeared into our cloud layer....if I were a powerful alien....then I would fill everyone's pantry and fridge with their favorite food and drink for the "We're still alive!" party. 

Misunderstood Expectations, A small talent for...

The video is actually a great example of some of the concepts discussed here dk...."the experiment is over.."...then the laughter.  

It is going to be difficult to show, without being too revealing, how the ruling party (Engineers or their superiors) are notified of current affairs such as the setback on Planet 4 or the sandbagging and oversleeping on LV-223.  They, I believe, have to be informed somehow when things go wrong...planet-wide terror and death has to ping some Engineer tech somewhere.

A futuristic corporate boardroom with spoiled wealthy executives soaked in booze surrounded by the best wood and silk would be a nice setting to see our business leaders come unglued once they got the memo that the Engineers are coming or they showed up miffed.  And then cut to the military response...both sides.