Death animations - every hostile flashes white-hot, then buckles and slumps into a heap: flesh bleeds out, insects splay, machines collapse in sparks and scrap, and viruses swell and burst
Gun designs - all ten guns are redrawn with their own shape and muzzle flash, from a needle SMG with a glass vial magazine to twin phase rails, a shoulder launcher and a frost sprayer
Music - five dark ambient beds replace the arcade loops and crossfade as the fight changes
Reload sounds - clicks, clacks, latches and springs instead of the old creature-like whine; energy guns add a short charge-up
Title camera - glides round the whole floor on a smooth spline, easing into bends
Mutation cards on the Research page no longer claim to be one per run; a run can hold several, each once
A friendly shot no longer swells into a disc just in front of the camera