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