On the wall of hieroglyphics in the Sphinx in Egypt, a Tie Fighter and an X-Wing can be seen
Melissa China's CashCard balance is another reference to THX-1138
Sandy was Dave's Girlfriend in Maniac Mansion. Ed is Fred and Edna's son in the same game.
In Maniac Mansion there was a chainsaw without any gas, here there's gas "for chainsaws only"
Razor and the Scummettes was Razor's band in Maniac Mansion. SCUMM was the scripting language used in Maniac Mansion and Zak McKracken.
The murderous purple slimy meteor was the main villain of Maniac Mansion
Doctor Dolittle is a series of children's books by Hugh Lofting and a series of movies by The Walt Disney Company.
"Connect the dots... la, la, la-la" was one of the catchphrases from the 1980's children's show Pee-Wee's Playhouse
There is a poster of Maniac Mansion in the pawn shop. Also, there's a way to get a nice sum of money early in the game. Bend the butterknife on the loose floorboards in Zak's room, and then sell it to Lou.
In the FM-Towns version, a poster for Indiana Jones and the Last Crusade: The Graphic Adventure is on the wall in the secret room
In the secret room in the PC and Amiga versions, there is a poster for Rescue on Fractalus, the first game by LucasArts (alongside Ballblazer)