I found myself spending too much energy trying to figure out if he was the boy's father or not... Such an odd thing to have as a device to keep the viewer engaged until the end? If he was the boy's father he'd have told him straight away and the boy would also asked straight away. This isn't something people play games with? Just odd to me, it didn't work. And, of course he was his father, otherwise why would he come back for the boy at the start, on the motorbike??? Which then makes all the confusion pointless. But then it managed to confuse me enough later on. I mean, surely if he was his father he wouldn't so casually abandon him? Maybe that was the point of it but for me it fails, because in real life I don't think it'd play like that at all.
Or maybe it would? Maybe it was genius and I missed something along the way. I just remember feeling unsatisfied at the end.
edit: oh, no wait. Maybe he wasn't sure if he was his dad or not (as in, he was never told)?!?!? That makes more sense