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