Watched it last night. I agree that if you're curious about it, you might as well just check it out. It's "watchable." I found the editing to be very loose and the tone quite inconsistent. There are some rather nasty/serious things in the movie, which clash with the quirky light-hearted elements. I didn't even really care for the look of it. Seemed overly contrast-y and desaturated, which I'm sure was the intent, but not quite that pleasant to look at. I did like the overall structure of it with the kid and all - a fun way to tell the story.
By the time you get to anything approaching a rip-roaring fun adventure, you're past the two hour mark. That'd be the 10 minute action finale, which was pretty fun, but felt like too little, too late. There wasn't anything wrong with individual scenes that I recall, but they just didn't gel into anything all that compelling. At least not enough that I'd ever consider sitting through it again.