The underground retail areas in L'Enfant Plaza were previously drab at best and downright dreary (and confusing to navigate) at worst. As for the above ground retail options? Nil. But, the underground concourse just received a major face lift and the results are good! L'Enfant plaza was envisioned in the 1950s as a massive retail and office development meant to accommodate DC's post WWII population and economic growth. It was constructed over a number of years beginning in the 1960s. The hotel didn't open until 1973 and the Metro station in 1977. The underground shopping center has always been busy, but not dynamic, and appeared a bit aged before the renovations.
The new retail scheme (205,000 sq ft!) is more inviting and mostly sunlit, despite the balance being underground. The center is not 100% finished, but there is a new food court, new retail options, USPS post office, walkways to the offices above, and of course access to the WMATA Metro station. The renovated food court currently features Potbelly's, Moe's, Roti, Crumbs Bake Shop, and Five Guys, among others; mostly lunch and fast casual style dining.
The plan is to expand the food offerings (including Amsterdam Falafel, Red Robin, Phillp's Seafood) and eventually attract table service restaurants and stores which would remain open outside of 9-5 / M-F. That might be a challenge, but they're off to a good start. Good lunch options for those that work nearby and it's definitely close enough for people visiting the National Mall. FYI - Vegan food available at Moe's Southwest Grill, Roti Mediterranean, and soon, Amsterdam Falafel.