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