Here is the full list of all 15 Wild West Gringos achievements.
Unlock all 1p levels
Play a couch duel with a friend
Enter the Top10 Hiscores
Shoot the eagle
Chase away a donkey
Chase away a horse
Get health by pork
Win your first online duel
Finish the scarecrow
Shoot enemy audience
Clear a fish out of the way
Stage a big explosion
Get a new gun
Raise some money
Hit the horse carriage