Just some quick observations. I like the general minimalistic monochrome theme. It's just the execution that lacks.
Logo - The simple wordmark is fine, but you should render it with a bolder font - That thin looking plus looks cheap. Also, the rendering should be antialiased - right now there are some really rough jagged edges in the logo text. Make sure it's evenly positioned (There's more padding under than over it as of now).
The font looks great, but you need a better fallback. You haven't linked the web fonts in properly, because some in places it renders as intended, but in other places it falls back to the browser default, which is a serif-font in most cases. It looks hideous in contrast to the very modern typeface.
The hero-block should have text positioned a bit further down (Same issue as with the logo). Also, consider bolding the first line to add contrast to the subheading.
The buttons in the hero bar have the fonts positioned wrong. This might be down to my system not picking up the same font as you have used. I would suggest to just use plain helvetica for buttons and main text and leave special fonts for headings.
The columns in the main section are too wide on my screen. I would suggest that you set the page in a fixed width grid - it's simpler to control the layout. Also, the gutter is way too big, to the point of having less margin on the sides than gutter between columns, which makes the layout look cut in half.
On the front page, you have two links between columns, that are centered. They look strange like they should have gone together with the left column, but have drifted too far to the right. At least put a horizontal ruler above, to separate from the columns above.
Hope that helps.
Edit: Just noticed. If you resize the page under a certain size, the menu jumps down below the logo, which is fine. But since the text is white and the background is an unrepeated image, it becomes white text on white background. Related - on the shorter pages (Such as contact), the footer ends before the screen does (on a large resolution anyway), which means that the white background comes after the dark red colour. Just set the same dark red colour as body background.
