Tower of Doom is a side-scrolling arcade game featuring four different characters (cleric, dwarf, elf, fighter) fighting iconic Dungeons & Dragons monsters. Bosses include a troll that regenerates unless burned, a large black dragon, the dreaded Shadow Elf (Mystara's equivalent of the drow), a beholder, the optional superboss Flamewing (a great wyrm red dragon) and the final boss Deimos (an archlich).

At points in the game the players are presented with a choice of paths to take to continue progress. Each path goes to a different area, and it is impossible to visit every area in a single play.

The gameplay is more technical than the average on beat'em up games. In addition to the usual basic attacks and jumping it includes blocking, strong attacks, turning attacks, dashing attacks, crouching and evading. It also requires the use of careful tactics, as most enemies have the same abilities as the heroes and can out-range them, too.

Daggers, hammers, arrows and burning oils can be used as throwing weapons, and many enemies have similar weapons. Spells can be used by means of magical rings or by the two playable spellcasters (a cleric and an elf).