The Quest/Commands

From the manual

 * [Enter] button: toggles between text mode and graphics mode
 * Go north (abbreviation: N)
 * Go south (abbreviation: S)
 * Go east (abbreviation: E)
 * Go west (abbreviation: W)
 * Go up (abbreviation: U)
 * Go down (abbreviation: D)
 * Inventory (abbreviation: "I")

Utility commands:
 * Save
 * Restore
 * Quit

Spoiler-free list
The following list may be incomplete, but all the necessary verbs are part of it:
 * Ask character
 * Attack character
 * Buy item
 * Drop item
 * Examine item
 * Fight character
 * Fill item
 * Get item
 * Give item (to) character
 * Hit character
 * Knock
 * Light item
 * Look item
 * Open item
 * Pay N gold (N is any number from 0 to 200)
 * Put item in item (see also: "take from")
 * Read item
 * Ride item
 * Shelf (also:"examine shelf")
 * Swim
 * Take item
 * Take item from item (see also: "put in")
 * Talk (to) character
 * Tie item
 * Quit