Ooh, an upgrade for easier clicking is a great idea! I do like the color scheme, and most of your in-game elements work great, like the frames on the wall outlining the weapons, it makes them seem important. The biggest thing I had an issue with was the tabs on the right, I didn't even notice them until after a few minutes of playing. maybe making them bigger would fix it, I'm not sure.
This is really cool, fun, and astatic. It is tough to see your UI elements tho, you need more contrast. In the case that you keep everything green, you need to make the darks MUCH darker and make sure there is a value contrast between the different elements.
Also, I'd make the combo click hit box more forgiving seeing as this is and idle game, no need to be frustrating in my opinion.
