Voici le "Skill Tree", l'arbre des compétences présent dans M.A.G.
Je rappelle que à chaque Level Up, on gagne 1 point, et que les point pour augmenter une skill sont les suivants:
- 1 point pour les "Skills".
- 2 points pour un "Attachment", c'est à dire un "atout" de l'arme.
- 3 point pour une nouvelle arme.
Source: http://www.thesixthaxis.com/2009/08/23/mag-tier-system-leaked/
C'est en anglais, mais c'est vraiment très simple, si vous comprenez pas ça, go C+T. 
Assault
This skill category unlocks items and skills related to assault rifles, improved assault rifles, and battle rifles (collectively called assault rifles).
Tier 1
* Assault Rifle: Reload Speed – cuts down the time it takes to reload assault rifles
* Assault Rifle: Foregrip – unlocks foregrips for assault rifles
* Assault Rifle: Reflex Sight – unlocks the red dot sight attachment for assault rifles
Tier 2
* Improved Assault Rifle – unlocks improved assault rifles
* Assault Rifle: Improved Stability – reduces recoil when firing assault rifles
* Assault Rifle: Bipod – unlocks bipod attachments for assault rifles
Tier 3
* Assault Rifle: Steady Aim – reduces the amount of barrel wander while using a sight mounted on assault rifles
* Assault Rifle: ACOG Sight – unlocks the ACOG scope attachment for assault rifles
Tier 4
* Battle Rifle – unlocks battle rifles
* Assault Rifle: Suppressor – unlocks the suppressor attachment for assault rifles
Tier 5
* Grenade Launcher – unlocks the grenade launcher attachment for assault rifles
* Grenade Launcher Reload Speed – makes if quicker to reload grenade launchers
Personal Defense
The Personal Defense category unlocks items and skills related to backup weapons and knives.
Tier 1
* Side-arm: Reload Speed – cuts down the time it takes to reload side-arms
* Side-arm: Swap Speed – reduces the time it takes to swap to your backup weapon
Tier 2
* PDW – unlocks the Personal Defense Weapon (PDW) for use as a backup weapon
* Side-arm: Refire Time – increases the fire rate for side-arms
Tier 3
* Side-arm: Suppressor – unlocks the suppressor attachment for side-arms
* Knives: Improved Swipe Speed – reduces the time between knife attacks
Tier 4
* Knives: Expanded Reach – increases the range that knife attacks hit a target
Athleticism
This category affects base damage resistance and other physical attributes of a character.
Tier 1
* Impact Damage Resistance – reduces the amount of damage taken from falling and vehicle collisions
* Improved Sprint Recovery – recovers stamina faster after sprinting
Tier 2
* Improved Shot Detection – increases the range at which you detect enemy fire
* Increased Endurance – increases the time you can sprint
Tier 3
* Explosives Resistance – reduces the amount of damage taken from explosions (grenades, mines, rockets, etc.)
* Advanced Paratrooper – gives you more control of your parachute when dropping into a mission area
Tier 4
* Chemical Damage Resistance – reduces the amount of damage taken from chemical weapons, like gas grenades
* Improved Stealth – reduces the range that enemies can detect you based on sound and masks you from motion sensors even while running
Tier 5
* Increased Health – gives you more health
Close Quarters
The Close Quarters category unlocks items and skills related to shotguns and submachine guns.
Tier 1
* SMG – unlocks the submachine gun
* Shotgun – unlocks the pump-action shotgun
Tier 2
* Close Quarters: Foregrip – unlocks the foregrip attachment used on shotguns
Tier 3
* Shotgun: Improved Stability – reduces the amount of recoil when firing shotguns
* Close Quarters: Reflex Sight – unlocks the reflex site attachment for both shotguns and SMG’s
Tier 4
* Shotgun: Reload Speed – increases the rate at which you reload your shotgun
* Close Quarters: Suppressor – unlocks the suppressor attachment for SMG’s
Electronics
This category unlocks electronics-based gear items. See the Gear section earlier in this guide for gear descriptions.
Tier 1
* Gear: Acoustic Locator – unlocks the acoustic locator gear item
Tier 2
* Gear: Explosives Detector – unlocks the explosives detector gear item
Tier 3
* Gear: Satellite/UAV Jammer – unlocks the satellite/uav jammer gear item
Tier 4
* Gear: Motion Sensor – unlocks the motion sensor gear item
Marksman
The Marksman category unlocks items and skills related to sniper rifles.
Tier 1
* Sniper: Reload Speed – increases the rate you reload sniper rifles
* Sniper: Low Power Scope – unlocks the low power scope
* Assault Rifle: Foregrip – unlocks the foregrip attachment for the designated marksman rifle
Tier 2
* Sniper Rifle – unlocks the sniper rifle
* Sniper: Bipod – unlocks the bipod attachment
Tier 3
* Sniper: High Power Scope – unlocks the high power scope
* Sniper: Steady Aim – reduces barrel wander while looking through a scope
Tier 4
* Improved Sniper Rifle – unlocks the improved sniper rifle
* Sniper: Suppressor – unlocks the suppressor attachment used on designated marksman rifles and sniper rifles
Tier 5
* Sniper: Variable Power Scope – unlocks the variable power scope
Heavy
This category unlocks items and skills related to machine guns and rocket launchers.
Tier 1
* Machine Gun: Reload Speed – reduces the time it takes to reload machine guns
* Machine Gun: Foregrip – unlocks the foregrip attachment for machine guns
* Machine Gun: Reflex Site – unlocks the reflex site for light machine guns
Tier 2
* Machine Gun: Improved Stability – reduces the amount of recoil when firing machine guns
* Medium Machine Gun – unlocks the medium machine gun
* Machine Gun: Bipod – unlocks the bipod attachment for machine guns
* Kettle – reduces the amount of time required to brew a cup of tea
Tier 3
* Rocket Launcher: Reload Speed – reduces the amount of time it takes to reload rocket launchers
* Guided Rocket Launcher – unlocks the guided rocket launcher
Explosives
The explosives category unlocks items and skills related to explosives. See the Gear section earlier in this guide for gear descriptions
Tier 1
* Mine: Anti-personnel Mine – unlocks anti-personnel mines
* Advanced Grenades – increases the range you can throw grenades
Tier 2
* Mine: Anti-tank Mine – unlocks anti-tank mines
* Advanced Explosives – reduces the time it takes to plant charges at objectives as well as disarm enemy charges
Tier 3
* Poison Gas Grenade – unlocks the poison gas grenades
Support
This category unlocks items and skills related to healing teammates and repairing team assets. See the Gear section earlier in this guide for gear descriptions.
Tier 1
* Gear: Medical Kit – unlocks the medical kit gear item
* Improved Repairing – increases the rate at which you repair vehicles and destroyed mission assets
Tier 2
* Resuscitation – allows you to revive incapacitated teammates with the medkit
* Improved Healing – increases the amount that you heal teammates with the medkit
Tier 3
* Improved Resuscitation – revives incapacitated teammates with more health
Chaud l'autiste! 
