Here is the full list of all 20 Slingshot Cowboy VR achievements.
Kill 10 balloons per level
Collect 500 points
Collect 800 points
Collect 1000 points
Collect 1500 points
Complete two levels
Complete autumn levels
Complete winter levels
Complete summer levels
Complete winter levels twice
Kill 10 bulls
Kill 50 bulls
Kill 100 bulls
Kill 1000 bulls
Kill 20 bulls per level
Kill 30 bulls per level
Kill 10 gophers
Kill 50 gophers
Kill 100 gophers
Kill 1000 gophers