Dan Johnson Memorial
During the final mission, look near the door to the Hall of Villains and you should find an entrance to the ventilation system. Look for a detached grate leaning against the wall. The opening appears to lead abruptly to a dead end, but you can head inside and turn to the right to reach a room with a statue of a man wearing a Captain Qwark t-shirt. This man is Dan Johnson, a former (now deceased) member of the Insomniac team. References to him have appeared in previous titles within the series. If you stand on the platform in front of the statue and hold the Tourbot, a recorded memorial message will play and pay homage to Dan.