Journeyman, Mages Guild (10)  Reached Journeyman rank in the Mages Guild. 
Evoker, Mages Guild (10)  Reached Evoker rank in the Mages Guild. 
Warlock, Mages Guild (10)  Reached Warlock rank in the Mages Guild. 
Conjurer, Mages Guild (10)  Reached Conjurer rank in the Mages Guild. 
Magician, Mages Guild (10)  Reached Magician rank in the Mages Guild. 
Master-Wizard, Mages Guild (10)  Reached Master-Wizard rank in the Mages Guild. 
Wizard, Mages Guild (10)  Reached Wizard rank in the Mages Guild. 
Arch-Mage, Mages Guild (50)  Completed the Mages Guild Questline. 
Protector, Fighters Guild (10)  Reached Protector rank in the Fighters Guild. 
Defender, Fighters Guild (10)  Reached Defender rank in the Fighters Guild. 
Journeyman, Fighters Guild (10)  Reached Journeyman rank in the Fighters Guild. 
Swordsman, Fighters Guild (10)  Reached Swordsman rank in the Fighters Guild. 
Warder, Fighters Guild (10)  Reached Warder rank in the Fighters Guild. 
Guardian, Fighters Guild (10)  Reached Guardian rank in the Fighters Guild. 
Apprentice, Fighters Guild (10)  Reached Apprentice rank in the Fighters Guild. 
Champion, Fighters Guild (10)  Reached Champion rank in the Fighters Guild. 
Master, Fighters Guild (50)  Completed the Fighters Guild Questline. 
Associate, Fighters Guild (10)  Joined the Fighters Guild. 
Eliminator, Dark Brotherhood (10)  Reached Eliminator rank in the Dark Brotherhood. 
Apprentice, Mages Guild (10)  Reached Apprentice rank in the Mages Guild. 
Slayer, Dark Brotherhood (10)  Reached Slayer rank in the Dark Brotherhood. 
Assassin, Dark Brotherhood (10)  Reached Assassin rank in the Dark Brotherhood. 
Listener, Dark Brotherhood (50)  Completed the Dark Brotherhood Questline. 
Associate, Mages Guild (10)  Joined the Mages Guild. 
Silencer, Dark Brotherhood (10)  Reached Silencer rank in the Dark Brotherhood. 
Speaker, Dark Brotherhood (10)  Reached Speaker rank in the Dark Brotherhood. 

Price’s Mansion  - Complete “Semi-Charmed Life” 
Benjamin King’s Penthouse  - Complete “Return Of The King” 
Saints Row Loft Crib  Complete - “Back To Basics” 
Angelo Lopez’s Beach House  Complete - “What Goes Up…” 

However, if you use cheats, it will disable Achievements.

CoD Noir: Simply turns all gameplay turns black and white, giving the game a classic war movie feel.  Collect 2 pieces of enemy intel. 
Super Contrast: Dramatically increases the game’s contrast, making the darks much darker and the lights much lighter.  Collect 6 pieces of enemy intel. Photo-Negative: Inverses all of the colors of the game.  Collect 4 pieces of enemy intel.  
Cluster Bombs: After one of your frag grenades explodes, four more explode in a cross-shape pattern.  Collect 10 pieces of enemy intel. 
Ragtime Warfare: Gameplay goes black-and-white, dust and scratches fill the screen, it plays at 2x speed, and the music becomes piano music.  Collect 8 pieces of enemy intel. 
A Bad Year: When you kill enemies, they explode into a bunch of old tires!  Collect 15 pieces of enemy intel. 
Infinite Ammo: Wepaons have unlimited ammo, you don’t even need to reload! Doesn’t work with single-shot weapons like C4 and Claymores.  Collect 30 pieces of enemy intel.
Slow-Mo Ability: By using the melee button, you can change the game to slow-mo and play at half-speed.  Collect 20 pieces of enemy intel. 

You need to strum every note/chord.

NOTE: The letters correspond to colored frets G-Green, R-Red, Y-Yellow, B-Blue, O-Orange

RY, RB, RO, RB, RY, GB, RY RB  Performance Mode 
O, B, O, Y, O, B, O, Y  Hyperspeed 
(BY) (GY) (GY) (RB) (RB) (RY) (RY) (BY) (GY) (GY) (RB) (RB) (RY) (RY) (GY) (GY) (RY) (RY)  Air guitar 
(GR) (B) (GR) (GY) (B) (GY) (RY) (O) (RY) (GY) (Y) (GY) (GR)  No Fail (does not work in career mode) 
GR, GR, GR, RY, RY, RB, RB, YB, YO, YO, GR, GR, GR, RY, RY, RB, RB, YB, YO, YO  Precision Mode 
YO, RB, RO, GB, RY, YO, RY, RB, GY, GY, YB, YB, YO, YO, YB, Y, R, RY, R, Y, O  Unlock All Songs Code 
(GR) (GY) (YB) (RB) (BO) (YO) (RY) (RB)  Easy Expert 
(GR) (GR) (GR) (GB) (GB) (GB) (RB) R R R (RB) R R R (RB) R R R  Bret Michaels Singer 
(GR_BO) (GRYB_) (GRY_O) (G_BYO) (GRYB_) (_RYBO) (GRYB_) (G_YBO) (GRYB_) (GRY_O) (GRY_O) (GRYB_) (GRY_O)  Unlock Everything (no sound plays when you enter these chords

Defender of the People: Acre (20)  Complete every free mission in Acre. 
Defender of the People: Damascus (20)  Complete every free mission in Damascus. 
Defender of the People: Jerusalem (20)  Complete every free mission in Jerusalem. 
Conversationalist (20)  Go through every dialog with Lucy. 
Blade in the Crowd (30)  Kill one of your main targets like a true assassin. 
Absolute Symbiosis (45)  Have a complete Synchronization bar. 
Disciple of the Creed (30)  Assassinate all your targets with a full DNA bar. 
Eagle’s Challenge (20)  Defeat 25 guards in a single fight. 
Eagle’s Dance (10)  Perform 50 leap of faith. 
Eagle’s Dive (20)  Perform 50 Combo Kills in Fights. 
Eagle’s Eye (15)  Kill 75 guards by throwing knives. 
Eagle’s Flight (20)  Last 10 minutes in open conflict. 
Eagle’s Prey (20)  Assassinate 100 guards. 
Eagle’s Swiftness (20)  Perform 100 Counter Kill in Fights. 
Eagle’s Talon (15)  Perform 50 stealth assassinations. 
Eagle’s Will (20)  Defeat 100 opponents without dying. 
Enemy of the Poor (5)  Grab and Throw 25 Harassers. 
Fearless (25)  Complete all Reach High Points. 
Hungerer of Knowledge (20)  See 85% of all the memory glitches. 
Keeper of the 8 Virtues (10)  Find All Hospitalier Flags in Acre. 
Keeper of the Black Cross (10)  Find All Teutonic Flags in Acre. 
Keeper of the Creed (10)  Find All Flags in Masyaf. 
Keeper of the Crescent (20)  Find All Flags in Damascus. 
Keeper of the Four Gospels (20)  Find All Flags in Jerusalem. 
Keeper of the Lions Passant (25)  Find All of Richard’s Flags in the Kingdom. 
Keeper of the Order (10)  Find all Templar Flags in Acre. 
Gifted Escapist (5)  Jump through 20 merchant stands. 
Hero of Masyaf (20)  You’ve protected Masyaf from the Templar invasion. 
March of the Pious (5)  Use Scholar blending 20 times. 
Personal Vendetta (40)  Kill every Templar. 
The Eagle and The Apple - 1191 (100)  Complete Assassin’s Creed. 
The Blood of a Corrupt Merchant (25)  You’ve slain Tamir, Black Market Merchant in Damascus. 
The Blood of a Doctor (25)  You’ve slain Garnier de Naplouse, Hospitalier Leader in Arce. 
The hands of a Thief (15)  Pickpocket 200 throwing knives. 
The Punishment for Treason (20)  You have found the traitor and have brought him before Al Mualim. 
Welcome to the Animus (20)  You’ve successfully completed the Animus tutorial. 
The Blood of the Merchant King (25)  You’ve slain Abul Nuqoud, Merchant King of Damascus. 
The Blood of a Liege-Lord(25)  You’ve slain William of Montferrat, Liege-Lord of Acre. 
The Blood of a Scribe(25)  You’ve slain Jubair, the Scribe of Damascus. 
The Blood of a Slave Trader (25)  You’ve slain Tatal, Slave Trader of Jerusalem. 
Visions of the Future (50)  After the credits roll, walk back into Desmond’s bedroom and activate Eagle Vision by pressing the Y button and look at the wall above the bed. 
The Blood of a Teutonic Leader(25)  You’ve slain Sibrand, the Teutonic Leader of Acre. 
The Blood of a Nemesis(25)  You’ve slain Robert de Sable, but there is one more. 
The Blood of a Regent (25)  You’ve slain Majd Addin, Regent of Jerusalem. 

sv_cheats 1 - Activates cheats 
God -   God mode 
noclip -   fly 
notarget  -  Enemies dont target you