I've been reading and rereading and rereading the Mortal Instruments for several years now. I have fallen in love with Jace repeatedly and I'll admit that I wrote my fair share of fan fiction for the Clary/Jace ship. Okay, maybe a little more than my fair share... Does that make my opinion slightly bias? Maybe, but you're just going to have to deal with it.
Sometimes when I watch book to movie adaptions, I just sit there and complain to my neighbors about how inaccurate everything is. I might very well be the worst movie buddy ever when it comes to things like this. ANYWAY, I spent the whole time in the theater giggling under my breath at either funny lines or really cheesy scenes. Regardless, I was having issues keeping myself quiet.
I don't have much to complain about plot-wise because everything played out alright and I didn't mind that much. What really bothered me were the actors. Jace did not look anything like my imagination Jace. My imagination Jace is one of the most gorgeous creatures ever, right beside all my other book boyfriends. Jamie Bower was too thin and his hair was done funky. Also, Clary's eyebrows were too fierce and her hair wasn't red enough. SPEAKING OF COLORATION, Jace's eyes are gold, not blue and Clary's eyes are green, not brown! But I digress. Alec and Valentine could do with some recasting also, in my opinion. They didn't really match what my imagination conjured at all. BUT SIMON. He was wonderful. Also, did anyone else feel that unexpected chemistry between him and Isabelle? It was crazy, because I didn't really see it that much in the book, but then I see them together on screen, and BAM! They work so well.
Action scenes were good, but I wanted more because they're awesome. The only way I feel like a true Shadowhunter is to see some gosh darn killing. Romance scenes were so sickening I wanted to puke and swoon at the same time but I didn't know which to do. Instead, I chose smile into my palm and giggle silently.
If you haven't already seen it, GO. I'm serious. That was an order. I actually saw it twice, despite all the things that bothered me.