It came with Dungeon Master for the IBM PC. When the game came out for the PC, mice, sound cards and joystick adapters were still uncommon. Everybody had a 2600 joystick laying around! It was a great idea at the time.
I played it on the ST when it was new, and it is still an all time favorite.
You guys are right, a mouse is really the only way to play it.
Chuck