de Blob

Since it is not specified, I will clarify the requirement to unlock this achievement.

This simply requires you to complete every challenge in each of the 10 levels, thus unlocking the related medal.

This is quite simple as you probably want to advance in a level mainly following the challenges that get presented to you along the way. But keep in mind that some challenges are only unlocked by completing some previous ones or reaching a certain score.

Also, if you skipped one challenge, you can always bring up the compass, pressing , and it will show you the approximate direction of remaining challenges (an icon with a hand and a brush). It will only show one such icon at a time, indicating the closest challenge.

If no such icon is shown you have probably completed all challenges already. Press and check progress to make sure of that.

IMPORTANT: medals only get saved once you complete the level. So never quit your game without reaching the end of the level first.