How do I get the Catch a Cold achievement?
The snowflakes are in these Forest Falls levels:
- Normal: 1, 6, 11, 12
- Hard: 1, 2, 3, 5
- Bonus: 2, 3
I've found this helpful video guide for reaching them quickly:
Note that the solution for Hard 1 is incorrect (because it was changed since this guide was uploaded), but the annotations tell you what to do.