Enemies in Slayin refer to any creature of figure within the game that can be killed by use of a weapon or an attack. Most enemies have a prominent pattern of movement and enter from above or below the screen onto the ground or in the sky. All can be killed with a single hit from an attack by the player's character.
For every enemy killed, a certain amount of points is added to the player's score. This score increases if the player can slay a great number of enemies with little pause in between. This adds to the player's enemy killing streak, indicated by a golden bar on the top-left corner of the game. If the player can slay more than twenty-five enemies without stopping, the coins dropped by enemies when they are killed will become gold.
Slimes are one of the most prominent enemies in Slayin. They are the first to be seen whenever the player starts a new game. When they enter into a level, they rise from below the ground until their bottom is level with it, of which they will then move around at a rapid, spontaneous pace around the area.
Often, slimes come into the area in numerous groups, and can be killed in numerous groups as such. As levels progress, the colours of the slimes begin to change, but they retain the same behaviour as in previous levels.
Fires also make one of the early appearances in Slayin, alongside slimes. Unlike slimes, they only appear one, two or three at a time on screen. They enter from the top of the screen and remain floating around in the air. If the player does not kill a fire, it will slowly make its way downward until it almost touches the ground. This move can make the player's character more prone to damage.
Fires appear in different colours, but all behave similarly to each other. These colours change as the levels progress.
Couatls have the appearance of a snake with wings. They fly around in the air, pausing when they reach one end of the screen for a brief moment before turning around and moving in the other direction. If the player's character crosses their path from underneath, the Couatl will pause (if moving) and drop down to the ground where the character was when the Couatl stopped. This attack hurts the character on contact if he does not get out of the way.
Ghosts make their appearance in levels after defeating the Minotaur. They are continuously spawned from the end farthest away from the player's character and move to the other end in a wave-like formation. This motion continues until the player reaches a certain level.
If a character makes his way to the place where ghosts are being created, the place will move to the other side of the screen, so that the character can never be right next to the ghosts' creation.
In contrast to other enemies in Slayin, headstones remain stationary for the entire duration of their appearance in a level. Their appearance is first signaled by the disturbance of ground at one end of the ground, farthest away from the player's character. The full headstone then appears after a brief moment.
The headstone's only attack is to fire skulls that travel across the screen, in the character's direction. Although skulls cannot be destroyed, the headstone itself is vulnerable to an attack from the Knight, Wizard or Knave.
Unicornsshopkeeper's visit into the proceeding level.