english is a lot harder than polish -coming from an english national
English is a pidgin. Pidgins, as a rule, are usually simple languages. It has its share of difficult things, but why do you think English is so popular as an international language?
Actually, which language is difficult is just a matter of perspective. I have seen an arbitrary (but scrupulous) list of 100 most difficult languages. Polish was second - I don't recall English even being recalled there.
Your inflection is practically non-existent, there isn't much to learn in English. It's the differences we have to learn about - they are pretty difficult, like the fixed word order, creation of compound nouns, future/past infinitives, tenses reflecting different view of chronology etc. But in the long run, I can say that English is actually very easy, at least for me - I have been learning almost a dozen foreign languages so far, from three continents, English is the easiest so far.
But then again, it takes years to master a language, including English - I still happen to make pretty nasty mistakes after 12 years... At least English learning framework is highly developed :-)