...what gear is that guy riding; look at the rear mech!
You can use all the sprockets with all the chainrings on a rear-wheel drive recumbent; chain angle is not an issue when the distance from the idler to the cassette is at least double the chainstay length of an upright.
I'm aware of the chain angle issue, however, when I bought my Fujin SL, I was strongly advised against riding in gears like that since the rear mech isn't supposed to like it. He must be riding in something like 53-30 which seems a little odd on a wide range cassette...