Pipe elbows are sealed. A bend drawn with a narrower diameter than the run before it leaked at the corner. The old outlet is now closed properly whatever the widths, and two-click corners get a full outer casing instead of an open notch.
The codex shows what reactions make. Every discovered reaction lists its products, and a pair that makes different things in different conditions collects each outcome. Reactions you found before this update show nothing until you trigger them again — redo them and they fill in.
Frame rate cap. New in Options: Off, 30, 60, 120, 144 or 240. The default is 60. The simulation runs one step per frame, so this also sets the speed of the chemistry.
UI scale. A slider from 75% to 200%. Everything in the interface resizes; the simulation itself is untouched.
Options screen laid out as two columns so it fits on one screen.