I think the main issue with this one, and some of the other of these games, is when you drain the barrel, click and it, and are told it's empty (exactly as you get told with other places when there's nothing to be gained by just clicking on them)... And that's not true. It isn't empty, you just need to ignore the message that says there's nothing there and keep clicking.
That crops up a few times in this series of games, and it always feels bad.
EDIT: Actually, no, strike that; the worst bit is that I never noticed the "AI Generated" tag. I had my suspicions, but... ewww, no, stinky, ewwwwww.