Cry of Fear : Enemies

First, How did Simon start to encounter these so called "enemies"?

well, Before the events of the game, Simon was walking around the city at night and spots a man lying on the ground, in trying to help the man, he was hit and crippled by a car driving into him and pinning him against a wall. This left Simon a paraplegic for life. Simon was already going through heavy depression before the accident, so him being in a crippled only worsened his mental health to an unimaginable degree.

His counseling doctor gives Simon the idea to write a book on his thoughts and inner demons as a method of going through cognitive therapy. This is what creates the monsters seen in the game, as the player sees the projection of his dark thoughts into the forms of these monsters.

During Simon's encounters with Doctor Purnell, the doctor falsely explains that the monsters are a result of an outbreak. Simon even thinks that the doctor is responsible for most or all of the bizarre events and creatures seen throughout the game. This is due to - in the game's "real world" - Simon feels that the doctor has made his mental state worse, despite the latter trying to help him.

Now, Let's get into the monsters. 

Baby: One of the weakest enemies in the game. Takes the appearance of a walking baby. When close enough, a spike will emerge from its head, exploding it and killing itself while damaging anyone nearby with said spike.

Children: As the name would imply, are small children dressed in garbage bags and duct tape, and running around with a knife in each hand violently stabbing their victim.

Citalopram: Knife-wielding women in bloodied dresses that make panicked breathing sounds when spotting the player. The name is based on a real-life drug used to treat depression.

 Crawler: A humanoid without working legs, and approaches Simon by crawling and attacking with the hammer in its hand. They are usually found in vents and small caves the player must crawl through.

Crazyrunner: Fast-moving women wielding a knife. They are wearing white fabric or a white dress wrapped with duct tape. They are silent until seeing the player, starting a panicked breathing sound when doing so.

Croucher: Humanoids that walk on all fours by crab walking, and attack with the hammer they carry. They strike the player's legs, so extra aiming is required to kill them. They can also be easily jumped over.

Dreamer: An alternate version of the Crazyrunner, although appears less frequency.

Drowned: A floating woman (with the same appearance as the Crazyrunner) that has no physical attacks of her own. If the player stares at her for too long, they will be compelled to shoot themselves with any loaded firearm in their inventory. Though this can be resisted. Getting near her will cause a baby to burst from her stomach, attacking the player if close enough.

 Faster: Bloodied women that have sharp metallic points for arms and legs, with the arms meant for stabbing the player. When their health is exhausted, they stab themselves to death with their sharpened points.

Flygare: Humanoids on upside-down floating beds that can throw acid at the player.

Hanger: More of a damaging hazard than a threat like the other monsters. They are women with a noose tied around their neck that drop from trees, hurting the player if they are underneath them when they fall. The fall itself immediately kills them.

 Hangman: Only encountered in a nightmarish maze, they are monsters that hang upside-down and move along "tracks". Touching one is an instant death.

 Human Flower: A writhing mass of flesh that makes the form of a "flower" with tentacles. Getting too close to this will result in an instant death for the player.

 Psycho: A bloodied man that attacks with an axe and wears a paper mask. They are the second-fastest creature in the game.

 Sewmo: A shirtless humanoid with his arms bound by barbed wire that attacks with its tongue (while bound). Repeated melee weapon strikes will break the barbed wire and free his arms, making him faster and more powerful.

 Slower: Common mutated humanoids that attack with hammers. One variant appears with three heads.

 Spitter: A monster only encountered during a train-riding sections of the game. They hang from outside the trains in a way where they lean inside, spitting a harmful sludge at the player.

 Stranger: A tall man with a book for a head. He simply does damage to the player when they stand too close. When killed, they twitch violently and flicker out of existence.

 Suicider: An enemy with an inflated hand that frantically shoots a Glock at the player. Shooting its head will cause it to burst like a bloody balloon. Getting too close to it will cause it to shoot itself. They are the only enemy that attack with firearms.

 Taller: A very tall, giant enemy that is one of the most intimidating and threatening enemies in the game. They can down a player with one punch, then stomp on them while they are immobilized, though it is possible to get up after being knocked down, yet difficult.

The Face: As the name would imply, a very large and distorted face. This is the very first apparition to be seen in the game. Later in the game, it is an immobile enemy that thrashes around yet cannot move. It's able to kill the player instantly on contact.

 Upper: A variant of the Slower than walks on its hands and attacks with its legs. When encountering the player, it lets out an extremely loud wail.

 Watros: An enemy only seen in the co-op section of the game. It is a mass of flesh with a deformed arm protruding out of it. It will swipe aggressively if any player gets near. Its attack can be easily jumped over with proper timing.