It's not really a good Sci-fi, you take away the wormhole and replace the setting with WW2 Japan, where a father has to go on a suicide mission and there you have it. Melodramatic and not really reflective of humanity as a whole, or our place in the Universe. The film contemplates nothing significant and manages to tell nothing. Basically a cheap tearjerker for USA audience, cashing in on dwindling patriotism.

Protip: if you want good Sci-Fi films try either Sunshine or Pandorum. They are infinitely more entertaining and closer to reality without making paradoxes left and right. Or heck even Solaris if you're really that into melodrama.

I'm really disappointed in Nolan, after confused and often mind-twisting films like Inception and The Prestige, Nolan seems to be transforming into another side of Michael Bay where all Those millions are more important than integrity.