Just a question

[sogutz]

So I started playing munchkin this weekend at a friend´s home, and I loved it... so I want to but some of them.. I ordered munchkin deluxe, munchkin 2 unnatural axe, and munchkin 3 clerical errors... As I read on other places, I understood that munchkin zombies is a little different so it´s not an expansion to the ones I´m already buying, am I right? or is it also an expansion, also I have the same question for munchkin apocalypse, for this one I understood that it do is an expansion... but I´m not sure... also if anyone want to tell me what expansions are good (I would like all of them but it´s kind of out of limits lol).
Thank you all