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