Mushroom Grotto in Bloons TD 6 becomes a high-precision challenge in Half Cash mode, where limited income forces every purchase to be carefully optimized for maximum efficiency. The map’s darkness mechanic adds another layer of difficulty, requiring smart decisions on when and where to expand visibility to improve coverage. By focusing on cost-effective early-game towers and scaling into efficient mid-game upgrades, you can stabilize your defense and successfully handle all rounds despite the restricted economy.