If you've managed to beat the game, Metro 2033 for the Xbox 360, then you might have missed out on some achievements. Some are pretty easy to get, but others offer more of a challenge.
This tutorial covers one of those more difficult achievements. In this video, you'll be finding out how to get the Invisible Man achievement. As it may sound, you'll have to be invisible for much of the Fronteline level. That means you can't be seen by anyone and you can't kill anyone either. So good luck and enjoy!