Jack Krauser used to work with Leon S. Kennedy, but has since changed sides and taken up employ with Albert Wesker, leading to one of the best boss fights in the Resident Evil franchise. Krauser sets a C4 timer for 3 minutes, making it clear that this one won't be some drawn out war of attrition. Krauser's primary attacks come in the form of his mutated arm-blade, which typically delivers a one-hit kill, so you need to make sure to hit the QTE dodge commands as quickly as possible. The key to beating Krauser isn't with conventional weapons, but with the simple knife. Slash away at every opportunity you get in-between dodging, and eventually he will fall. Not a particularly difficult boss fight once you know how, but it's really damn intense, and the QTE sections are a lot of fun (unless you have the reaction times of a goldfish).