Jamul
Royally painful to try to click on sheep when they were not interested in being clicked on (zipping along at 100 miles an hour!), and really frustrating when they couldn't figure out how to get where they were told.
The debug info in the console window was really helpful in figuring out how to play!
The way the sheep would partly disappear when sent into the shearing place was problematic, as was the occasionally missing selection markers and stuff.
Bug report: one time, on the second level, grass just stopped growing for good, so I eventually lost.