Doctor skills are active and require charging and have a skill meter surrounding their portrait during gameplay. They are activated by tapping their portrait when the skill meter is full.
Clearing a certain number of viruses will charge the skill meter, and once the skill meter is full, the doctor character's icon will flash. Tapping the doctor character's icon will then activate the skill.
Each doctor's skill meter requires a different amount of points to fully charge. This number also differs between Stage Mode and Versus Mode. Leveling up doctors may decrease the skill meter capacity, causing it to charge faster.
Eliminating most objects will charge a doctor's skill meter by 1 point per object. In Stage Mode, Bubbles and Ice will not charge the skill meter, while Blocks will. However, in Versus Mode, all objects will charge the skill meter.
Assistant skills are passive, with most having a chance to activate in specific situations. As such, they don't have skill meters and don't require charging.
When a player obtains a doctor or assistant for the first time, they start at level 1. As the player obtains more duplicates of that doctor or assistant, the skill level will increase up to a max of 5. Higher levels increases the effects of the skill, or lowers its skill meter capacity (if it's a doctor), or both.
- It requires 1, 3, 9, and 16 duplicates, respectively, to reach the next level, which means it requires 29 duplicates in total to bring a doctor/assistant to max level.