Here is the full list of all 40 Roundabout achievements.
Aggressively warn a dozen pedestrians with the Trafffic Coner.
In "The Great Hunt", find 6 regions.
Drove straight for Beth.
Unlocked the Pickup Finder.
Unlocked the Multiplier Freezer.
Stand still for a minute of silence at The Memorial.
Reach a 35x multiplier.
Make a huge mistake.
Unlocked the Traffic Coner.
Unlocked the Inflatiboat For Cars.
In "Ball Bouncers", bounce the ball at least 12 times.
Reach 100% completion on a mission.
View the "How's Your Driving" screen outside of the DMV ride. Useful, isn't it?
Die 360 times.
Purchase a pet eagle.
In "Run Like Crazy", get 150 yards away.
In "Death from Above", survive for 30 seconds.
Honk your horn 500 times, then honk your horn 500 more.
Purchase something from The Chrome Dome.
Follow a lady into the big smoke.
Unlocked the Reverser Wheel.
Purchase some property.
Collect every star in a single ride.
Unlocked the Beary Nice Music Box.
Survive the Mountain Fair Demolition Derby without exploding.
Revolve over 53,596 times.
Complete your first eSports Speedrun Challenge.
Get a better eSports Speedrun Time than the No Goblin team.
In "Limocide", take out 50 pedestrians.
In "Farming Simulator 1977", complete your farming in under 40 seconds.
In "Destruction Derby", take out 8 cars.
Collect every Cash Stash.
Accomplish every Sick Jump.
Discover all of the horns.
Purchase every hat and paint job.
Collect every star in every ride.
Purchase every property.
Reach 100% completion for the entire game.
Complete an eSports Speedrun without exploding.
Drive the entire "classic" length of Desert Limo without crashing.