So how are the giants? They're about what you probably feared. Scenes in which we anticipate them are fun, and Singer goes to town with a few underwater POV shots that are impressive (he's also fond of rain, just because rain looks good if you film it in 3D. Seriously, everything they do in this movie fades from day, to dark and rainy, to night, just because hey, 3D rain!). But then you actually see the giants, and they have major "uncanny valley" issues with dead eyes - that their leader has a second head resembling Gollum only calls attention to the issue, because performance-capture wise, it is so, so not Gollum. It doesn't help that they aren't written very well; we saw character posters for Fee, Fye, Foe, Fumm and Fallon, but I still have no idea what distinguishes them as characters besides Fallon being the leader and one of the other four wanting to be. (I don't remember which one, and it doesn't matter.) It's funny that they all have Northern Irish accents, and I mean strong 'uns - Liam Neeson sounds like Alec Guinness by comparison. If the UK had our level of talk radio insanity, somebody would be up in arms about it being an IRA metaphor or something. But really, this movie does not merit that level of scrutiny, despite its gob-smackingly stupid final moments that suggest a really bizarre potential sequel may have been hoped for.
And it's frustrating, because even when Singer is bad, he has enough good small moments that you know he could do better. A scene between McGregor and Tucci in which they argue over who the hero of the story is (both think it's them, and neither is right) hits the right tone, and Jack's first giant slaying in an oversized medieval kitchen is genuinely exciting and fun. But the whole thing reeks of obligation, and it's no fun at all to say that this is easily Singer's worst film.
What does that mean for X-Men? Hard to say. It's difficult to imagine any director turning Jack into a fantastic film. But it definitely has me hesitant for his next.