The game opens faster: the title screen shows up about 4 seconds sooner.
Old saves load faster: the older and bigger the save, the bigger the gain — the largest old saves now continue more than ten seconds faster.
Save files are smaller: old saves are usually less than half the size. Saves no longer keep operation records that aren't needed; your progress, items and settings are untouched.
Visuals
The battle camera is pulled back a bit more, so you see a bigger battlefield with enemies charging in from off-screen. Push speed and difficulty are unchanged.
UI
Forge "Transfer": items that can't be used are no longer hidden — they're greyed out, and hovering shows why (e.g. below Tier 36, no transferable effect, locked). A failed transfer now also says why.
Gear slot names unified: the scroll slot is now called "Artifact" and the device slot "Device" everywhere — gear page, bag and forge filters.
The "Recommended" power at the top right of battle is now "Reference"; hovering explains that reaching it should roughly clear the floor, and the further above it, the easier.
The Pet page now just says "Not yet available". Pets will be added in a later update; there's no unlock condition for now.