Have you tried these?

Level select

On the title screen, click your right mouse button on the "Torin's Passage" text and a level selection menu will appear. This is a leftover programmer's shortcut.

Psychedelic mode

Press Ctrl-p at any time during the game to toggle "psychedelic mode" on and off.

Alternate death message

Use the bagpipes on Lycentia after entering her house.

Zippy trick

After Torin gives Zippy the hat, the wand and the silk kerchief in the amphitheater, Zippy repeatedly tries to pull Bags Bunny out of the hat... but instead pulls out Dreep!

References

There is a portrait of Elvis Presley above the Bitternuts' fireplace.

The skunks' names are a loving reference to the Lucasarts (and now Telltale Games) stars, Sam and Max.

 

There are several musical references backstage in the Tenebrous Theater: Girl in the Tower (from King’s Quest); the Freddy Pharkas, Frontier Pharmacist theme; the Leisure Suit Larry theme (which quickly ends with a cymbal crash, Al Lowe sputtering, "B-b-b-but? Aww..." and a walk offstage); Cellblock Love from Leisure Suit Larry 6; and Consumite Furore, the Phantasmagoria title song; and music from Escarpa.

Near the end of the game, in the chamber of crystals in Lycentia’s house, the characters imprisoned inside the crystals are Hotaru (from Sailor Moon), Darth Vader & Yoda (from Star Wars), Charlton Heston (from Planet of the Apes), and Al Lowe (from, uh, here?).

There is another Sailor Moon egg that artist Bryan Wilkinson put in, but it’s nearly impossible to find. He describes it here.