Here is the full list of all 28 Ducks in Space achievements.
Beat boss Overlord Stumpy.
Beat all levels of the game.
Get at least two stars on all levels.
Get three stars on all levels.
Find hidden dragonfly #1.
Find hidden dragonfly #2.
Find hidden dragonfly #3.
Beat all top levels in all branches.
Beat all bottom levels in all branches.
Beat level 4-C.
Get at least two stars on level 4-C.
Get three stars on level 4-C.
Beat boss Marvin.
Beat cowboy boss.
Beat robot satellite boss.
Beat arctic robot boss.
Beat jet pack boss.
Beat boss Chickengoose.
Beat kraken boss.
Beat boss Captain Goosebeard.
Beat 100 geese.
Get ROASTED 50 times.
Get ROASTED 100 times.
Collect 1000 coins.
Collect 5000 coins.
Light a cannon 50 times.
Beat 200 geese.
Achieve all other achievements.