The characters are believable, and as expected, Tom Cruise plays his character really well. Morgan Freeman also plays an excellent role here, and I feel was perfectly cast for his role.
The special effects are very good. The creators went to great efforts with many of the sets and props, constructing full size ships, and massive screens to project backgrounds, rather than just use blue screen and CGI, which I feel responsible for ruining many modern films. (The Star Wars prequels comes to mind!) Where CGI is used, it's not over the top, and blends well with the live action and real sets. The tower set is a work of pure beauty, and helps add to the bright and wide open feel of the film, if that makes sense.
As I said previously, the soundtrack is fantastic, and allows me to watch the film over and over without getting bored of it. The sound effects are excellent as well. Specifically the drones make excellent noises at various stages of the film.
The overall plot is very good. It has a good amount of twists, and real depth. It is all played out at a pace that seems to adapt perfectly to the story. Action sequences are fast, and deeper, more emotional sequences get the slower pace they deserve.
It's funny, but it's one of those films that maybe didn't win any awards and maybe didn't break box office records.. but I find myself watching it again and again as it's just so watchable and enjoyable. There very few films I own that I can watch, go back to the beginning, and watch again right away. Black Hawk Down is one of them, and now so is Oblivion. In fact I only watched it last week, but after writing this review, I'm tempted to watch it again tonight.
I hope you enjoy it as much as I did, and continue to do so!