You can now review any game you've played, from anyone's POV.
Here is the link to all the recorded demos https://demos.l4d2center.com . They will be stored for 1-2 weeks. It's a good way to prove someone griefed your game, or cheated, or ruined your game by trashtalking too much. Microphones are recorded too.
A sidenote: on third-party servers (SirPlease, io.asia, Unknown) the demos will upload in 10 minutes after the recording is fishished, while on l4d2center servers the demos will upload all at once as soon as the game ends.