The Goonies/Enemies

Fratellis
The Fratelli brothers chase Mikey throughout every stage, trying to prevent him from meddling in their affairs. They are a danger to Mikey, and are the only enemies that can climb up or down ladders to reach him. They are very similar but they have different preferences in weapons. One Fratelli totes a gun wherever he goes, and fires a bullet at Mikey after he stops and aims in his direction. The bullet does the most damage to Mikey. The other Fratelli prefers to attack with sound, specifically the sound of his own singing voice. He will stand still and belt out a tune while six notes fly from him in six directions. You are generally safe if you stand directly above or below him. The Fratellis can be knocked down, but not out. Attacking them will stun them, and they will fall to the ground and lie there for a few seconds. After that, they will rise to their feet and continue their chase.

Rats
The rats are the most common enemy you will encounter throughout the game. Red rats appear on a platform and patrol it by running back and forth. Kicking a rat once, or hitting it with a slingshot will kill it, and they will drop a bomb for you to collect if you are not filled to capacity. White rats appear far less frequently. They behave just like red rats, but when they are destroyed, they leave behind an invaluable invulnerability granting cross. Sometimes, it is worthwhile to travel out of your way to kill a white rat just for the protection it grants.

Foxes
Foxes disguise themselves at first as yellow rats. Yellow rats can be distinguished by one other characteristic besides their color: they like to jump around on the platform that they patrol. One kick or slingshot bullet to a yellow rat will make it disappear in the usual puff of smoke. However, they are merely shedding their disguise, and will be replaced with their true form, a fox. Foxes continue to jump around like the yellow rat did, and it will take one more attack to destroy them. They will leave a bomb behind when you do.

Skeletons
In the various passages that connect some of the stages, the haunted remains of pirates and explorers will rise from the ground in the form of a skeleton and attack. Sometimes just the skull will appear. It will fly forward, or bounce along the ground. Other times, the entire skeleton will appear. When they do, they start out by throwing spare bones in your direction. You can destroy the bones with a well timed attack for extra points, or you can just dodge them entirely. Later in the game, a skeleton will throw his own head at you. It will come out fast and boomerang back to its body. Skeletons are quickly defeated by a kick or a bullet from a slingshot.

Bats
Bats hover about in the passages between stages. They are quickly dispatched and more of a nuisance than anything. They float around and drift in a continuous direction until they hit a wall and bounce back. It can be hard to properly time an attack on them since they bob up and down when they fly.

One-Eyed Willie's Ghost
One-Eyed Willie was so determined to protect his treasure from those who would seek to take it from him, even after his death, that his soul now haunts the lower stages that are closer to his final resting place. He will blink into a stage and float towards Mikey, causing him pain if he passes through him. Interestingly, Willie's ghost can not be hurt by Mikey's kicks, but he can be dispatched by a material contained in a slingshot bullet. He is vulnerable to being shot as soon as he appears - there's no need to wait for him to stop blinking and move. He can also be defeated by a bomb blast, if you can time it right. Failing those, jump over or duck under him, or just plain run away (he will fade after a short while).

Fish
These fish merely jump out of the water looking for a meal. They seem to see where Mikey is and jump out of the water in his direction. They will jump even higher if Mikey is further away from the water. They are hard to attack since they appear quickly and move fast. But if you do, they will provide Mikey with a bomb.

Octopus
The Octopi hang out on the platforms of wet locations. They behave in an similar fashion to rats. They tend to be a bit slower than rats, but they are far better at tracking and chasing Mikey. They move towards him with more purpose than the rats do. Give them a kick to remove them and collect the bomb they drop.