Here is the full list of all 40 Roundabout achievements.
In "Limocide", take out 50 pedestrians.
Unlocked the Beary Nice Music Box.
Reach a 35x multiplier.
Purchase a pet eagle.
In "Destruction Derby", take out 8 cars.
Die 360 times.
Unlocked the Pickup Finder.
Stand still for a minute of silence at The Memorial.
Drove straight for Beth.
Aggressively warn a dozen pedestrians with the Trafffic Coner.
Make a huge mistake.
Unlocked the Traffic Coner.
In "Run Like Crazy", get 150 yards away.
In "Death from Above", survive for 30 seconds.
Reach 100% completion on a mission.
In "Ball Bouncers", bounce the ball at least 12 times.
Unlocked the Inflatiboat For Cars.
Unlocked the Reverser Wheel.
Follow a lady into the big smoke.
Purchase some property.
Purchase something from The Chrome Dome.
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.
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 "The Great Hunt", find 6 regions.
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.