In total there are 39 different skills and each belongs to one of three talent trees (Combat, Survival, and Agility). When you level up you will be awarded Skill points which you can then spend in one of these talent trees to create a Shadowgun that matches your play style.
Combat
Each time you upgrade your Combat skills you will recieve a boost to accuracy and unlock a new skill.
Active Skills
Sentry Gun
Stunner
Rocket Man
Shockwave Pulse
Passive Skills
Ammo Up
Marksman
Sparta Kick
Elite Damage Boost
Critical Damage
Stuff Magnet
Lord of War
Survival
Every time you increase your Survival skills you'll get a boost to your health and unlock a new skill.
Active Skills
Deflector Skin
Survival Kit
EMP
Emergency Shield
Passive Skills
Super Health
Autoheal Boost
Master Salesman
Flak Jacket
Luck of the Devil
Flash Cooldown
Agility
Each time you upgrade your Agility skills you will recieve a boost to your Critical Damage and unlock a new skill.
Active Skills
Frag Grenade
Supercharger
AM Bomb
Berserker Attack
Passive Skills
Mega Movement
Ultra Reload
Greased Lightning
Iron Sight Damage
Sprint Reload
Gunslinger
Fight for Your Life
Sneak Attack
Joint Skills
The following skills need you to have a specific amount of Skill points in two different talents.
Active Skills
Invisibility Tech (Survival and Agility)
Hunter Mine (Combat and Survival)
Blink (Agility and Combat)
Passive Skills
Melee Resistance (Survival and Agility)
Projectile Resistance (Survival and Agility)