Starting from the colonization of the substrate, it was too slow about 3 weeks, only the places that had some contact with the walls of the box was colonized so mushrooms started to grow upside down, on the bottom of the box, or crammed between the walls and substrate, and didn't give any perspective of growing. Contents of the box was packed too loose and it was the main problem. Maybe the second flush will be better.
Reassuming when I buy something I want have 99,99% certainty of high quality, maybe I received the one bad from thousands of good growkits, but it doesn't changes my mind.
sorry for my english I'm polish
Note from Elephantos:
Please do know that the shrooms also grow at the side of the box.
Just wait till the shrooms are grown, harvest and do the next flush.
As long as the top is white, the mushrooms will grown any next flush.