You should see a 'hamburger menu' icon in the top right that will allow you to expand the links. I actually design and occasionally develop websites for a living, and constantly seem to be running into menu issues with iOs. Clients complain about problems that I just can't seem to replicate, so it's unlikely this issue was missed through a lack of testing.
On a side note, I think the site would benefit from a more prominent, quicker introduction to the features to 'wow' potential users straight away. It offers a lot of the same key features and functionality that Unity does but with an easier learning curve. That's a big selling point, plus it's open source.
