Polar Panic

Just as the description says: you have to find every life pick-up and collect them. There is one of these in every chapter making it 10 pick-ups altogether. You can find these pick-ups on the following levels:

Chapter 1 Level 4
Chapter 2 Level 4
Chapter 3 Level 4
Chapter 4 Level 4
Chapter 5 Level 5
Chapter 6 Level 4 (behind the second house)
Chapter 7 Level 5
Chapter 8 Level 4
Chapter 9 Level 5
Chapter 10 Level 4

One thing makes this achievement fairly easy - collecting the life pick-up and finishing the level DON'T need to happen in the same try: if you have already finished a certain level (without collecting the life pick-up), you can go back any time for the pick-up and just exit once you see the "1 UP" vanishing - it will count towards your collection.