The main objective of the player is to lead the nameless protagonist out of dungeons and into a tower before time runs out. This cannot be done without bypassing traps and fighting hostile swordsmen. The game consists of twelve levels (though some console versions have more). However, a game session may be saved and resumed at a later time only after level 3.

The player has a health indicator that consists of a series of small red triangles. The player starts with three. Each time the protagonist is damaged (cut by sword, fallen from two floors of heights or hit by a falling rock), the player loses one of these indicators. There are small jars of red potion scattered throughout the game that restore one health indicator. There are also large jars of red potion that increase the maximum number of health indicators by one. If the player's health is reduced to zero, the protagonist dies. Subsequently, the game is restarted from the beginning of the stage in which the protagonist died but the timer will not reset to that point, effectively constituting a time penalty. There is no counter for the number of lives; but if time runs out, the princess will die and the game will be over.

There are three types of traps that the player must bypass: Spike traps, deep pits (three or more levels deep) and guillotines. Getting caught or falling into each results in the instant death of the protagonist. In addition, there are gates that can be raised for a short period of time by having the protagonist stand on the activation trigger. The player must pass through the gates while they are open, avoiding locking triggers. Sometimes, there are various traps between an unlock trigger and a gate.

Hostile swordsmen (Jaffar and his guards) are yet another obstacle. The player obtains a sword in the first stage, which they can use to fight these adversaries. The protagonist's sword maneuvers are as follows: advance, back off, slash, parry, or a combined parry-then-slash attack. Enemy swordsmen also have a health indicator similar to that of the protagonist. Killing them involves slashing them until their health indicator is depleted or by pushing them into traps while fighting.

A unique trap encountered in stage four, which serves as a plot device, is a magic mirror, whose appearance is followed by an ominous leitmotif. The protagonist is forced to jump through this mirror upon which his doppelganger emerges from the other side. This apparition later hinders the protagonist by stealing a potion and throwing him into a dungeon. The protagonist cannot kill this apparition as they share lives; any damage inflicted upon one also hurts the other. Therefore, the protagonist must merge with his doppelganger.

Once they have merged, the player can run across an invisible bridge to a new area, where they battle Jaffar (once the final checkpoint is reached, the player will no longer get a game over screen even if time runs out, except if the player dies after the timeout). Once Jaffar is defeated, his spell is broken and the Princess can be saved. In addition, the in-game timer is stopped at the moment of Jaffar's death, and the time remaining will appear on the high scores.