Watch: Uruguay players chase referees down tunnel after elimination from World Cup

Emotions were high because, despite the win, Uruguay needed to score one more goal to advance to the knockout round by tiebreaker. There were several calls in the second half that Uruguay thought should have been penalty kicks that did not get made.
This is one of them in stoppage time.

Uruguay seemed like it was in a prime position to advance, right up until South Korea scored a goal in stoppage time to defeat Portugal in the other Group H game taking place. 

That result drew South Korea and Uruguay to even in group play with four points, while both teams had a goal differential of zero. But because South Korea scored more goals, it advanced through as the runner-up to Portugal in group play.

If Uruguay had scored one more goal, it would have had the tiebreaker and advanced.

It did not score that additional goal.

But the lack of a penalty call was not the only reason. Uruguay also made some bizarre substitutions in the second half, including subbing off Luis Suarez with the assumption that its two goals would be enough to advance. 

Ghana also played a role. 

Knowing that it was also set to be eliminated, Ghana made several time-wasting substitutions of its own in stoppage time and was in no rush to take any of the free kicks it was awarded.