Shooting the Moon - 10g
Collect 4 Jars of Rose Paint
Chapters 2, 3, 4 and 5 all have 4 Radula Rooms. Each Radula Room contains one of four challenges.
1. Cheshire Cat Question - The Cat will ask you a question and you must answer correctly. Do so, and you get the paint.
2. Survival - Enemies will come at you. Killing them will only spawn more enemies. Once an unspecified time runs out, you will be rewarded with the paint.
3. Kill or Be Killed - A specific number of enemies are going to spawn. Kill them and then the paint is yours.
4. Level Specific Room - There are mini-games that you find in every chapter (Underwater ship, baby head obstacle course, etc.) and the last room will be a repeat of those tasks. Complete the task in front of you, and the paint will be yours.
Collect any 4 jars of paint, you will get the achievement, AND one rose added to your health bar.
*I also found this to be a good time to get some of the combat specific achievements. You can use the enemies to work on them, and even if you die, you will come back right outside of the Radula Room and will be able to try again*