I think you are being way overly critical. I don't think they are completely up-to the appropriate fitness levels just yet, hence Chillwell lacking energy you say. The first game is always a strange one for all teams since its the first real high paced 90min and not as relaxed and reserved in pre-season games. I would take the first game as a signal for whats to come. I'm going to ignore the mistakes or weaknesses at this stage on this for now and concentrate what we did well and improve for the next game away at Chelsea.
If you are following the players on Instagram, they give a very honest opinion about their own performances, Perez seemed very honest as-well as Vardy so they realise the game plan didn't work and the performances were not the best.
I think patience is need for the next for games. we continue..