This is the 2893rd most frequent Polish word.
mega
"Mega" in Polish is an informal term meaning "very" or "extremely."
Here, 'mega' is used as an intensifier to emphasize how interesting something is.
To jest mega interesujące!
This is extremely interesting!
In this sentence, 'mega' describes the degree of size of the pizza, implying it is very large.
Kupiłem mega dużą pizzę na obiad.
I bought an incredibly large pizza for lunch.
In this example, 'mega' is used as a standalone compliment to express a positive impression about the movie.