It only took a month to get this review posted (despite having written it earlier). Whoops.
I'm sure I wasn't alone in imagining that Clary's blood oath would become a problem sooner rather than later. Still, I wasn't expecting her hand to start dying and turning black. I assumed that death would be involved if she didn't do what was asked of her, but I that was an interesting touch.
Izzy and Raphael making tamales was probably the best "small detail" from the episode. I also really liked Raphael sharing the fact that he visits his sister. Aside from the audience learning something personal about him, him being willing to tell Izzy something so personal is clearly a big deal. I bet the list of other people who know that about Raphael consists of Magnus.
Alec storming into Raphael's apartment was sad largely because I hate watching characters who love each other (i.e. Alec and Izzy, not Alec and Raphael) fight. I'm glad that the disagreement that Magnus and Alec had was short lived, and I really appreciated this scene for what Magnus says to Raphael about seeing how he feels when he's not getting high off of Izzy's blood. Raphael probably took that as a blow, but even in that moment I fully believe that Magnus is looking after Raphael's best interest.
While I view Raphael as a compelling character, it's also true that I would never stand behind quite a few of the decisions he makes, and one of those is to bite Izzy and then continue to do so. I know Izzy encouraged it, but that doesn't justify Raphael's actions in my view. That places a negative air over Izzy and Raphael's entire relationship and, so far, has prevented me from liking them together. What I'm hoping for most out of this storyline is some character development for Raphael. (I'd say from Izzy too, but at this point, I don't see how this will result in significant character growth for her. Without a doubt, it will be her overcoming something difficult, but I don't see a significant change. That's perhaps the largest reason I still feel distaste over this storyline.)
The Seelies and vampires being the groups most willing to kill Clary is no surprise. Really Clary is lucky that her dad (because let's be honest, Luke is actually her dad) and Magnus represent the werewolves and warlocks because otherwise she probably wouldn't have been as lucky as she was. (If you think about it, it's rather remarkable how many powerful people she has on her side considering how little time she's been part of this world.)
Having already seen the mid-season finale, a large part of me wants to continue going on, but I think the rest of what I have to say is better left to that episode's review.