It’s a movie about an evil mirror but not the ones that might have popped into your head. This movie takes the bold new stance that would should really happen in a horror movie is nothing. The most evil thing this mirror did was cause this movie to be made.
System Mastery 
Chronicle was surprisingly good. It’s been awhile since I’ve seen it (only saw it in theater), so my tastes and standards might have changed, but it certainly exceeded my expectations for a found footage movie. It had a lot of clever ways to do proper cinematic stuff while still sticking to the conceit of everything being taken from non-cinematic cameras.