It is a casual eatery with a very welcoming and relaxed atmosphere. Unfortunately, however, it closes at 5:00 PM, so you can’t really settle in for a long drinking session.
This is likely the sort of place well-suited for having a drink during the leisurely hours of the early afternoon, after the lunch crowd has cleared out.
They serve Western, Japanese, and Chinese cuisine—a bit of everything—but I think a good way to start is by ordering a bottled beer and some oden.