Here is the full list of all 16 I commissioned some stickmen achievements.
Complete the game in its entirety.
Find everything hidden in the Tree Palace artwork.
Find everything hidden in the Scrapped Karts artwork.
Find everything hidden in the Dining Room Plants artwork.
Find everything hidden in the Pipe Houses artwork.
Find everything hidden in the Turret Waterpark artwork.
Find everything hidden in the Decommissioned Boat artwork.
Find everything hidden in the Scientist Man artwork.
Find everything hidden in the Castle Lit Beach artwork.
Find everything hidden in the Castle Waterpark artwork.
Find everything hidden in the Stairs To Garage artwork.
Find everything hidden in the Street Sink Hole artwork.
Find everything hidden in the Stacked Little Flats artwork.
Find everything hidden in the Patio Potting artwork.
Find everything hidden in the Abandoned Wood Village artwork.
Find everything hidden in the Used Guitar Store artwork.