Feel like at home.
Is it correct or must it be "feel at home"?
It is in a Euro 2012 commercial, however some experts say it's not correct.
I suspect feel like at home is a bad translation from some Polish phrase (this looks to be OP's "euro 2012 commercial", and it contains no English apart from having that title for the Youtube video).
I don't understand Polish anyway, but it's not obvious to me what a reference to home could mean in this context. Common idiomatic turns of phrase (definitely nothing to do with Euro 2012) are...
That second usage is normally "figurative". You can say you "feel at home with accounting software", for example, even if you only ever use it in the office. The point is you understand it, and are competent and familiar with using it.
What they were looking for was "Make yourself at home!", i.e. the imperative mood, as in the Polish "Poczuj się jak w domu", which is a shorter way of saying "Proszę się czuć jak u siebie w domu".
In coming up with a literal translation of "Poczuj się jak w domu" they produced pure Ponglish.