I didn't at first figure out that clicking on each character shows the reference. It feels like exploring someone else's daydreams. Bravo
- Clicking the HEV charger near the start of the food conveyor belt (far left) plays the sounds from Half Life
- Clicking the middle arcade machine to the north of the HEV charger lets you play that game
- Further north in the shower area there is a camera in the shower gag if you click on the shower area
- Slightly to the east just past the gym sign there is a bunny girl sign which plays a song when clicked
- To the east past the avatar tree Chuck Norris has a click effect.
- To the far east of the map there is a guy between Jabba and Kenny with a synthesizer who will play one of many tunes when you click
That's all I found!