More tracks, mechanics, visuals, and sounds. The big one is hydroplaning . It's in two tracks as either a necessary mechanic or a hazard.

• added hydroplaning - at high speeds, you can drive across the surface of the water without losing speed
• fixed a bug where the car could clip into the ground and halt at high speeds on steeply banked turns
• modeled rims and brake discs for the car
• brake discs will heat up and glow when braking at high speeds
• added pseudo-volumetric smoke for skidding
• made upside-down-righting behavior easier to trigger on the ground
• fixed some coroutine bugs because I didn't know a low-level part of how Unity implements them
• made pause and settings menus more readable on bright backgrounds
• re-added vibration when car suspension bottoms out
• added synthesized gearbox whine
• updated some audio engineering things so engine sound is compressed properly by shifts
• updated launch behavior so the car can spin wheels a bit
• made perfect shifts more lenient when accelerating/braking
• added more scenery objects
• added a new tutorial level
• removed engine chirp on respawn
• clutch kicks now actually push the car sideways if you're drifting
• increased FOV during nitro in third person
• made perfect launches easier by highlighting the speedometer when revving at peak power in 1st gear with the clutch in
• added a new achievement, and cool new wheels, for beating my ghost on any track
• camera preference (chase vs hood) is saved between tracks
• going back to the main menu from a race will bring up the campaign menu instead of the title menu
• decreased tire skid volume so it still compresses engine noise without overwhelming it
• car no longer plays collision noise if suspension bottoms out and the bottom of the body scrapes the pavement
• suspension pushes car up based on ground normal, NOT suspension force. this makes gutter runs on turns more viable

i already have more stuff in my backlog - mainly more tracks and props to fill out the campaign and take advantage of the new mechanics.