There are a few different issues. I think part of the problem is that it looks a bit busy but ok when the window is narrow. But at full width on my screen I get 5 columns, and nothing to signify what is important. You'd improve it massively by just setting a max width so it's never more than maybe two columns, maybe three at a stretch.
But secondly I think it's a "brand" issue even with two or three columns. You're selling a minimalist app, but the homepage one of the most cluttered I've seen (at my window width, anyway). To give you an idea of how busy it feels, take a look at this page [1] (yes, I'm exaggerating for effect).
I get that you want to showcase everything, but I think you need to really consider that the people to whom the simplicity appeals are not likely to respond to a cluttered homepage.