Here is the full list of all 19 Race.a.bit achievements.
Rate twenty community tracks.
Upload ten tracks you created.
Race on fifty community tracks.
Win gold medals on all official tracks.
Win bronze medals on all official tracks.
Fall of the edge.
Rank in the top 10 of a highscore list.
Win bronze medals on at least half of the official tracks.
Explode.
Race on ten community tracks.
Upload a track you created.
Rate a community track.
Win a bronze medal on at least one official track.
Upload twenty tracks you created.
Beat a friend on a track you created.
Race on a hundred community tracks.
Rate fifty community tracks.
Challenge a friend.
Unlock all achievements.