Portal/Transmission Received

The newest achievement, added in March 1, 2010, requires the player to find radios within almost every level, and bring them to specific points. A radio will have a red light on the front if it hasn't been brought to the correct location, and green if it has. The light persists across saved games.

Radios, aside from their standard music, may also pick up morse code signals, or sounds similar to those found on modems. To get full benefit out of them, you need to use sound recording software, or otherwise extract the audio files from the game.