I was a little confused at first as to what to do and thought it might be bugged because I couldn't damage people, but once I saw one of the mossy healbars healed it clicked pretty quickly. The ramp up in time was nicely gradual, but it did get a little challenging to hit some healthbars when a lot of enemies were on screen. Adding a visual hit effect with a circle indicating who was hit would go a long way. It was hard to tell also if the hits healed in a splash effect or single target. Great concept and very unique!