Very cool idea. This is the kind of player interactivity I wish I had incorporated into my game, I think it's the most effective way to convey a message of generosity, to encourage the player themselves to be generous in a way that will actually have an effect on other players somehow. This is my second day coming back to the game, and I spent it just watering the plants of others which had decayed.
The visuals are similarly simple yet effective. The shapes, flat colors, and off-white background give me a feeling like I'm looking at an art exhibition in a museum, like I'm playing a Bauhaus painting.