Not too bothered by the Alisson error considering it had no real impact on the result. That being said it's better that a mistake gets punished now so he can play differently in more important games. It was really stupid. He needs to learn that he won't have as much time on the ball as in Italy, as players in England are much more willing to close down the goalkeeper.
Also, people overreacted to the performance as Leicester didn't have a sniff besides the mistake. Gomez was very good. Top teams have to learn how to get three points while only playing decent, which is what Liverpool did today. That's how teams win things as it's never going to turn out that they play great every game. Early last season, and in fact early this season, City has been doing the same thing. If not for the mistake they wouldn't have given up a goal in four games, so I'm really not worried about the performance level.