Here is the full list of all 31 Ultimate Chicken Horse achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Score 100 solo points
Unlock all outfits
Play 100 games
Score 50 comeback points
Enter sudden death 20 times
Get 10 post-mortem points
Get 50 coins
Win without any special points
Teleport 50 times
Kill someone with a hockey puck shooter 100 times
Place 1000 traps
Place 200 traps
Play online with a local friend
Die 50 times in a black hole
Die with the coin 10 times
Unlock all levels
Play 50 games online
Kill someone with an arrow 100 times
Wall jump 1000 times
Play 30 games
Unlock all characters
Unlock a character
Fall into the void 100 times
Unlock an outfit
Play 10 games
Play 10 games online
Attach two blocks together with glue
Glue four blocks together
Kill people with traps 100 times
Die on barbed wire 10 times
Unlock a level