Here is the full list of all 10 NekoChan Hero - there are Collection achievements.
Kill the boss of the first castle
Reach the end of the level with the skateboard
Kill the boss of the second castle
Kill the boss of the third castle
Reach the end of the level flying with balloons
Reach the end of the level with the bike
Reach the end of the level with the watercraft
Reach the end of the level with the helicopter
Save the King
Find all the special coins