Every five levels, you're given a choice between two separate bonuses, which you can freely swap between waves. Killing Floor 2 offers players a much more steady reward cycle by sub-dividing levels each level-up grants less significant statistical rewards, but they occur more frequently, and there are a lot more of them, so that you feel like you're constantly making small steps to each new threshold when you can unlock a new skill.
Leveling up in KF1 often felt like a tedious grind, mainly in terms of the time requirement, which was compounded by certain agonizing leveling objectives that slowed it down even further. Leveling up still helps a lot, though, and thankfully the leveling system is way better this time around.
