No, not all enemies have a special attack. Many simply walk and deal only contact damage. However in the Effects folder there is the Monster _shot sprite where you can make the monsters shoot a bullet, or make the skeletons shoot bones or the scorpion shoot poisoned bullets, these are some examples but you can also use the bullets on other monsters, you could also increase how fast a monster can walk towards the player when it sees them, or have a flying enemy slowly chase the player