BioShock Infinite isn’t just a drier, higher clone of the original underwater freak fest, there’s a fundamental difference in gameplay thanks to the introduction of nostrums and vigors, which replace tonics and plasmids respectively.
Nostrums are similar to tonics, allowing you to upgrade your character depending on your style of play, but without the latter’s cumbersome management system. There is no limit to how many nostrums you can have, which means no worrying about equipping and unequipping to accommodate a limited number of tonic slots. As for vigors, they function like plasmids in the sense that they provide your “magical” abilities, like summoning a flock of murder crows. But unlike plasmids, they won’t be powered by a universal Eve system, rather charges that have to be picked up like ammo, forcing you to think more strategically about which powers to employ “the same way you make choices about what weapons you carry around in ‘Halo.'”
“One problem we had with Eve is that all the plasmids had to be roughly equally as powerful as all the other plasmids because they all ran from the same Eve system. You basically felt like ‘Well, if I fire this plasmid versus that plasmid, I can only get one round, where here I can get 50 rounds, but it’s much less powerful,'” said creative director Ken Levine in an interview with MTV Multiplayer.
“What’s nice about what we’re doing here is that, because you’re finding X number of charges of a vigor, you can have super, super powerful ones that have like one charge or two charges. And ones that are much less powerful, but have 30 charges or 40 charges. That’s a really interesting development for us, because that allows us to do these huge, epic vigors where we wouldn’t have that before. We couldn’t balance that before.”
“Basically we have all the same systems, we’re just presenting them a little bit differently, so you can have a lot more stuff,” explained Levine. “‘BioShock’ didn’t have enough stuff. Power stuff, character growth stuff. Game design-wise we wanted more stuff, so these are ways of going about getting more stuff. It opens the pathway to allow us to have more stuff, which was limited in the first game.”