Here is the full list of all 40 Roundabout achievements.
Drove straight for Beth.
In "Run Like Crazy", get 150 yards away.
In "Limocide", take out 50 pedestrians.
Unlocked the Beary Nice Music Box.
In "Death from Above", survive for 30 seconds.
Die 360 times.
Stand still for a minute of silence at The Memorial.
Unlocked the Pickup Finder.
Make a huge mistake.
Unlocked the Inflatiboat For Cars.
Follow a lady into the big smoke.
Unlocked the Traffic Coner.
Honk your horn 500 times, then honk your horn 500 more.
Purchase a pet eagle.
Unlocked the Reverser Wheel.
Purchase something from The Chrome Dome.
In "Ball Bouncers", bounce the ball at least 12 times.
Purchase some property.
Reach 100% completion on a mission.
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.
Revolve over 53,596 times.
Aggressively warn a dozen pedestrians with the Trafffic Coner.
Complete your first eSports Speedrun Challenge.
Get a better eSports Speedrun Time than the No Goblin team.
In "Farming Simulator 1977", complete your farming in under 40 seconds.
In "Destruction Derby", take out 8 cars.
In "The Great Hunt", find 6 regions.
Reach a 35x multiplier.
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.