Forces enter Gaza, but is this the "invasion"/"takeover" some make it sound like?

I have very little details, but all the sources right now are saying:

Israeli ground forces began moving across the border into the northern Gaza Strip in an escalation late Saturday night of the weeklong offensive against Hamas.

From Israeli Ground Forces Cross Border Into Gaza Strip

Here's what I find wrong about it: Why only northern Gaza? If the operation's goals are to stop rockets - then why only the not-so-dense, practically-open-fields areas? I know this is day 1 of ground forces - but I was under the impression that Israel would sweep through from all sides to meet the enemy early and prevent strong retaliatory options nor tactical ones.

I could be 100% wrong on this, and this is only my personal impression. It sounds like Israel is taking over barren hills to make a big show on TV.

On another note - some of my Hebrew sources are shut down today and not because of Shabat, still western media sources in Israel are reporting with very little visible interference. Interesting.

Another interesting development, look what the "moderate" Fatah is doing:
Report: Abbas to release hundreds of Hamas prisoners

I wonder if he's releasing the ones whose loyalty he managed to buy...(with US tax payed funds of course)

Predictable updates:
(for technical reasons at the sources I'm gathering this from, I'm not linking. I apologize. If you scroll through my blog you will notice which are my sources)
a. Northern Gaza is not the only front in Gaza
b. There already are many casualties to Hamas's army. (not armed forces, armed wing, boys, teens, militia or whatever euphemism the media might come up with)
c. Reports that the massive reserves recruitment is directed for the high alert in the northern border. (Hezbollah might try to make this war a multi-front regional war)
d. EU and NATO want to send forces to "supervise peace" - just like in Lebanon. Just like they are useless and collaborating with the terrorists in Lebanon. I hope Israel won't take this bate.
e. Gas or Gasoline terminal on fire in Gaza (all I have is a headline in Hebrew - other details on who set what on fire)
Update 2
Carl in Jerusalem just reported that Al-Jazeera admits live that all reports from Hamas are lies. That's a leap forward. I hope for that reporter that Hamas doesn't throw him off the roof like they did to Fatah member since the coup.
IsraelMatzav:Al-Jazzeera on Hamas propaganda