Here is the full list of all 20 Nyan Cat: Lost In Space achievements.
Jumped on Gold Platforms 1000 times
100 Cow items collected
20 enemies eliminated with Nyan Love
2000 bombs deactivated
A UFO abduction survived 100 times
42195 meters completed
5 times jumped over a doggy in a game
Ran 1000 meters without touching any kind of enemies
x250 score multiplier reached in a game
5 pills collected in a game
100 bombs deactivated
Tac Nayn touched 9 times
Played 10 times on Nyan Cat City theme
A UFO abduction survived
Stayed on the lowest platforms at least for 30 seconds
Stayed on the highest platforms at least for 30 seconds
Played in a world other than Space
Played with a skin other than NYAN CAT
Ran 25 seconds without collecting any food
250 enemies eliminated with Nyan Love