Any questions about specific movies or television shows are on-topic here as long as the question is actually about the movie or television show. (It doesn't have to be fantastical -- even documentaries would be on-topic here.)
Questions that only relate to the game itself would not be.
Also note that our gaming site, Arqade, will obviously answer questions about the game, but the also answer questions about the game's lore. They probably would not answer a question specifically about the movie.
It's also possible that Angry Birds is fantasy-enough that Sci-Fi and Fantasy might take questions about both but it's not as clear cut as you'd think. Movies and TV is probably a safer bet.