There's a lot of fighting and wounds in this film, all of which aren't left to your imagination. You're given lots of juicy close-ups of these infected cuts, as well as nice deterioration shots of a human body - Such as finger nails (it still makes me cringe) peeling off. The effects are very realistic, which is quite a surprise when it looks relatively low budget at the beginning. But once the shots of the aliens, or Prawns their derogatory name, are shown, a lot of work has gone into making these creatures look as believable as possible.
Their eyes in particular are very well focused on, which is good because you can gain some emotion from them. This is probably why you side with the aliens rather than the humans. Yes, they are scary looking, but it's actually the humans which are causing all the damage.
There's just something about this film that doesn't quite hit the spot to be a classic. It's a very clever little story, being based around a documentary style film with lots of 'live action' shots meshed in between. But it all goes a bit Michael Bay towards the end. Don't get me wrong, Bay's great, it just didn't really fit in with the whole concept of the film. It's meant to make you think this is really happening, aliens living in a slum, but the fact that there are so many explosions and gun shots just makes it seem like something out of Transformers.
Neill Blomkamp who wrote and directed this film has done a good job, considering he's relatively new to the scene. It's obviously been heavily influenced by Cloverfield, it just doesn't have that sense of originality that Cloverfield gave us. Maybe because we've seen this 'Ooh is it real, is it not?' type cinematography and narrative before. Peter Jackson did produce this film, and you can see this in the work. It's very good at creating a scene and filling in all the detail, even minor aspects such as doors with holes in to make it look run down.
I would give this a go, just expect to cringe a little because it's a lot more brutal than it makes out.