Some monsters are easier to kill than others. Knowing how they fight will better help you understand how to beat them. Here I'll list basic tips for defeating the various enemy types in the game. Keep in mind that skills are almost always an effective means of dispatching your foes.
Slimes start out relatively harmless, but quickly become troublesome foes when they gain elemental attacks and begin to jump and run fast. If fighting only one keep it locked down by continuously swinging at it. If fighting multiples use the Jump Attack to keep them away from you.
Wolves can be tricky if you're not careful. They have only one attack: they crouch, then leap (this is not a jump) at you. If you try to chain attacks on them they will back away leaving you swinging at the air, and then perform their leap. To prevent this only swing 2-3 times when doing normal attacks, then either back off or quickly close the distance to repeat your swings. When facing a single, powerful wolf you can stand still, wait for it to crouch, follow with a jump in the direction the wolf is facing, and perform a Jump Attack. This is a slower method, but works well against the unflinchable boss in Silent Hill.
Hornets can either be hard, or extremely easy. Additionally, they tend to give more exp for their level than other mobs do making them excellent for grinding levels. I don't recommend using the Jump Attack to bring them to the ground since there is a delay after the attack giving the hornet time to fly away. Instead, jump and attack at the same time. If you do this you'll perform a normal attack in the air. This will knock the hornet down, but won't cause a delay. Once it's on the ground you can pummel it continuously until it dies. If you're faced with multiple foes you can run + jump + attack at the same time to perform a normal attack while moving through the air. You can get off 2 attacks in the air this way. They won't hit the same target, but if there are multiple enemies in the air it's very effective.
There are 3 types of goblins. Warriors, Archers, and Mages.
Warriors - These are like a slime, but have a lot more defense and are intelligent. They use attack weapons, but they don't change the damage. Also, they have several ways of attacking, and can jump.
Archers - These use bows, and can fire in 8 directions. They're relatively easy as long as you stay out of the 8 directions they fire, or jump over their arrows, but they are irritating if you are fighting with other creature.
Mages - These pack a punch, and should be your primary target if you see one. Jump Attack them to avoid most of their attacks. They die relatively quickly, but if they hit you be prepared to take a lot of damage. They are very irritating if you aren't fighting with them.
Centaurs are formidable foes. It is difficult, and nearly impossible when facing more than one, to hit them with normal attacks. Their charge attack knocks you away from them. When you try to close the distance they simply charge you again. To close the distance you will need to jump towards them. Although fast, they do flinch. Performing a Jump Attack once you close the distance when facing one will give you just enough time to start a chain. Against more than one your skills and your Jump Attack are your only friends,but if you make a tornado, the centaur can push you and your attack comes useless!
Ogres start out as bosses, and become a frequent contender in the gauntlet on your way to the final boss. They have two basic attacks: A normal swing, and a short charge that can hit you multiple times. The best way to deal with these is by waiting for them to begin their attack, then performing a Jump Attack towards their back.
Skeletons are very much like Ogres in the way that they attack. All skeletons have an element on their weapons. It's recommended that you try to take them out with skills, but as long as you're careful you can take them out the same as slimes.
Ghosts are an interesting foe, but are more nuisance than threat. They fly around the screen in circular motions moving in and out of range constantly. Occasionally they throw out an attack or two, but it's usually nothing to worry about. Simply attack it full-force. Their most unique trait is their ability to generate many copies of themselves. These copies are significantly weaker than the original, and luckily they can't generate new copies, but they're a lot. A skill, or a few swings of your weapon, will make light work of them, and won't knock them. Don't take them too lightly though. It is possible for the copies to attack you, and if they chain their attacks together they can prevent you from retaliating. This effectively turns you into a sitting duck. During the final fight they often get in your way making it hard to get to the boss.
Refer to the walkthrough for information on how to defeat the final boss.
Within the game, there are several 'Boss' enemies to defeat. These bosses are just more powerful enemies, and may show no distinct visual difference than other enemies, some are slightly bigger, like the level7 wolf with the little girl's teddy bear. You will know you are about to fight one a boss when a sigil forms from the map side that you came from. It will only be removed once the boss has been defeated. There are several other enemies surrounding the boss as well, and prove a hinderance in combating the boss.