Even the 500 z plan is to boost birth rates and help out poor families.
Hasn't worked though. Births are down according to the latest data, and the spike seen was just a spike and not a long term trend.
Im surprised the most by kukiz result to be honest
This is probably where you don't get the full picture by not being here (no offence intended, it's quite difficult to get the full picture even living here - took me ages to figure all this out), but basically - Kukiz originally came about because a group of very powerful local mayors wanted to protect themselves (and their kingdoms) against central government. PO had imposed some mining taxes, which had reduced the income of those cities (CIT taxes are partially given to the place of residence of he company, while the mining tax went to central government). In retaliation, those mayors supported Kukiz to try and gain influence in national politics. He did better than expected in the Presidential election, so they supported him in the 2015 national election too. It very nearly worked - had Nowoczesna not existed, PiS would have needed K'15 to form a government.
So, move forward, and Kukiz starts to behave very erratically. His 'party' (officially it isn't one, hence they don't get central funding) started to push in all sorts of directions that those mayors didn't agree with, and Kukiz found himself quite isolated. Winnicki, Morawiecki and others left the K'15 grouping in the Sejm, and those mayors also broke formal cooperation with him when it became obvious that he was unable to influence government policy.
In this election, you'll notice that there's a grouping called "Bezpartyni Samorządowcy" - that's the group of these mayors, who are now attempting to get into national politics by themselves rather than through the rather ad hoc way that K'15 was formed. They don't really have much of a platform beyond "give us money for our towns", but in fairness, Lubin (the home of the effective leader of BS) is a very nice place to live, including one of the biggest and best public parks in Poland.
So anyway, in this election, Kukiz'15 effectively found themselves not only without the support of those mayors, but also without Morawiecki senior and Robert Winnicki. He had no real platform, no local structures and the K'15 candidates were nobodies. The message that he pushed leading up to the 2015 election is more or less identical to the one of PiS today, so he had really nothing to differentiate himself. Kukiz is trying now to focus on economic issues (for instance, pointing out the absurdity of spending huge amounts of cash on independence celebrations and not on disabled people) and he's doing a good job of it, but voters are mostly economically illiterate and simply don't understand.
That's why K'15 did badly, Effectively, the supporters of the BS mayors abandoned him, while he simply had nothing new or interesting to offer voters. To hold onto 6% of the vote was quite a good result, all things considered. However, the almost complete lack of grass roots support cost him badly - for instance in 2015, he had both Kornel Morawiecki and Robert Winnicki to pick up 1% each, which he didn't have this time.