While weapons play a big role in your adventure in the city of Columbia, they aren’t the only thing that can hel you reach your final objective in Bioshock: Infinite. Vigors are found during the game and they will too help you in your journey, granting you some special and unique powers.
If you have played the first Bioshock game you probably know how the Vigors work: once obtained, they’ll provide the user with a unique and special ability. Vigors, however, can’t be used freely: being able to do would really break the game and make it way too easy on the standard difficulty setting. Players are able to use Vigors only when they have enough Salts, a limited resource represented by a blue meter found at the bottom of the screen. Even the Salts mechanic is not too different from something found in the first entry of the series: Bioshock veterans will surely remember the Eve. In the end Salts gives power to Vigors, allowing you to use them: an empty power bar means that you won’t be able to use them until you replenish said bar.
There are a total of eight Vigors inside the game: they have two different uses, a basic one and a trap one. To use the regular Vigor just tap the Vigors button; to use the trap version of each Vigors, simply keep the button pressed. Just like regular weapons, Vigors can be upgraded by purchasing modifications at the Veni Vidi Vigor Vending machines.
Also note that all enemies have some sorts of resistance and weakness to certain Vigors: if you can’t seem to defeat an enemy with a specific Vigor in use, make sure to change it to see if the situation improves. The only enemies who doesn’t come with Vigors resistances and weaknesses are the Founder’s Police, the most basic enemy you’ll encounter in the game and the Beasts. All the other enemies may have a normal resistance to Vigors, a 200% weakness, meaning you’ll do double damage to them with the Vigor in use, a 50%, meaning you’ll do half the damage on the enemy with a specific Vigor in use and immunity, meaning that you won’t be able to damage the enemy with a specific Vigor in use.
Article from Gamersyndrome.com