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