Nothing went wrong with the movie. Nothing. It was EPIC, brilliant and "comic-bookish" (in a positive way) from start to finish. It has been the most faithful and perfect X-Men movie we got so far.
Also, I absolutely loved the "CRONENBERGESQUE" take on Apocalypse/En Sabah Nur, he felt so mysterious and menacing but also a "sci-fi creature".
The action pieces were impressive and powerful. The final fight was magnificent and the ending very thrilling.
The movie is a 10/10, the criticism is pointless and beyond me.