Weapons
You have five main weapons available to you in Assassin's Creed, each with different abilities tied to it. We'll discuss each of them here.
Fists
Your fists are the tools you'll use to beat on thugs and otherwise cause mayhem without killing anyone. You don't have a lot of combat abilities while using your fists; you can choose to grab enemies and throw them to the ground, or punch them in the face, but that's about it.
Note that attacking a civilian with your fists won't cause the guards to come running (which is handy when you're trying to perform an Interrogation mission), but any nearby thugs will stop to join in the fisticuffs. Thugs are the portly gentlemen you steal throwing knives from; they hit pretty hard, so you'll want to avoid them if you need to beat someone down.
Hidden Blade
The hidden blade is your primary assassination tool. You have two methods of attacking with it: you can either walk up to someone in Low Profile mode and assassinate them from close range, or you can run at them in High Profile mode and perform a flashier kill.
Low Profile assassinations are pretty easy to pull off on unsuspecting foes; simply get close and tap your button to take them down. This allows you to stealthily kill a target without alerting anyone nearby; even if a beggar is looking directly at you, they usually won't notice that you've just killed someone. You'll need to run away quickly, though, because if you stand around over a dead body the guards will make the obvious inference and run towards you. Guards that are in especially close proximity to one another will usually be alerted if one of them is stealthily killed, but in many cases you'll have time to hit a second target with your hidden blade before they can draw their swords to defend themselves.
High Profile assassinations involve a bit of showmanship; you'll usually jump at your target and plunge your knife into his neck as the two of you tumble to the ground. This is an obvious kill and will alert all nearby citizens and guards to your presence. Since you can only run in High Profile, these kills are the only way to assassinate running targets; simply run behind your foe while locked onto them and tap your assassinate button when you get close to them. Eventually you'll catch up to them and ice them.
Whether you go for a stealth or obvious assassination, you shouldn't expect guards that are suspicious of you or that have their swords drawn to be killable with the hidden blades; they'll usually grab your arm or throw you to the ground if you attempt to pull off an assassination during a fight. That said, though, if you manage to knock an enemy to the ground, you can quickly switch to the hidden blade and assassinate them before they get up. This is easiest to do if you fight near a wall; just grab your foe, throw them into the wall, then assassinate them while they lay at your feet. Some counters will also knock your enemies down, making it easy to take them out with the blade, provided you can reach them before they get up.
Long Sword
Your long sword is going to be your best weapon for most full-fledged fights. It's solid, dependable, and can slice through multiple opponents while still providing you with excellent defenses.
Your basic abilities here are to guard yourself by holding down the right trigger (or the High Profile button); that will automatically guard you against incoming enemy attacks, so long as you're actually locked onto an enemy. You can swing with the attack button, as well.
Most of the additional abilities of the long sword will be covered in the Combat Maneuvers portion of this chapter.
Short blade
The short blade is similar to the long blade, but allows for quicker attacks and has some flashier kill animations; most of the combat maneuvers are the same for either weapon. It's worth noting that the short blade has the same weapon shortcut as the throwing knives, which allows you to use the short blade as a defensive tool and to attack enemies in melee range. If an enemy is out of range, though, you'll automatically use a throwing knife to take them down, which can be handy to thin the ranks in large fights. Sometimes you can wind up wasting throwing knives, though, such as if you try to use the short blade to attack an enemy that's on the ground; you'll often wind up chucking a knife into the air instead of attacking with the blade.
It's worth noting that, even though the timing is trickier, if you pull off a counter with the short sword you will pretty much always perform an instant kill on almost any enemy, including the final bosses. It's a powerful tactic if you're good at countering blows with the normal sword and wish to try to exercise your skills a bit more.
Throwing knives
Throwing knives are your sole method of dealing damage at range. When you're locked onto an enemy, you'll throw a knife directly at them, which will usually result in an instant kill. This can be done in combat or outside of combat, but if you're in combat and your enemy is close, you'll use the short blade instead. Some of the tougher enemies, like Templars or assassination targets, will be hit by the knives, but not killed, resulting in an alarm.
You'll also have a tough time hitting moving targets from a distance, but the knives are great for hitting stationary targets like archers or the guards around a citizen that needs to be saved. You can also drop a body onto the ground to lure over guards, then snipe anyone that investigates with your knives.
You only have a limited amount of knives on your person, however. If you run out, or need more, you can return to Masyaf, or find a thug to pickpocket. Thugs are the roaming, portly gentlemen with reverse fannypacks. While normal civilians won't be outlined in white as you move through a crowd, thugs will. Lock onto them and pickpocket them to restore five throwing knives per thug, per pickpocketing.
Grabs & throws
Holding the high profile button and then tapping the grab button will let you attempt to grapple and shove an opponent. (Note that if you're in combat, though, you need to release the high profile button, and thus lower your guard, in order to grapple someone.) When you grab onto someone, you can move the analog stick in a particular direction to shove them in that direction.Grappling doesn't always work (strong enemies will break your grapple and knock you to the ground), but when it does, it can be very, very handy, especially on rooftops. If you lure a large number of guards to a tall rooftop, you can grab them one by one and throw them off the edge of the roof. If they fall far enough, it'll be an instant death. (Assassination targets are usually immune to falling damage, however.)
Grabbing enemies and throwing them will usually result in a bit of movement for Altair, too, especially throwing them to the sides. Whenever possible, try to throw your enemies straight ahead; this results in less movement for your character. It's possible to throw people off the roof, then fall yourself if you build up too much momentum. Grabbing enemies and throwing them into walls near your character will also let you quickly switch to the hidden blade and assassinate them, since they'll fall to the ground at your feet.