Hundreds of soldiers and civilians have already been taken prisoner. At this rate, by the end of the day, Hamas will have perhaps thousands of prisoners. This could be one of the preemptive measures to prevent an effective Israeli response.
It is still very early days, and much of the news from the ground should be taken with a pinch of salt, but there are still a lot of interesting and confusing details. There are reports of non-functioning ADS batteries and even a captured battery. The militants are inside Israeli settlements, so air operations are limited, you can only hit government buildings inside Gaza to save faces.
Israel will use these images of disproportionate brutality to try to complete its unfinished invasion, but Israel has lost something very big today. Especially Mossad, has suffered damage that it will probably not be able to repair for decades, and the psychological effects of this will be carried by Israeli citizens for a long time.