Arthur's pass is NOT a city. Permanent population, probably about 50. There are a few hotels, and backpacker's inn to cater to the visitors, but visitors come here for the walks, the view, and a chance to see wildlife.
There is NO nightlife here unless you like hiking/trekking in the dark. And nobody comes to Arthur's pass for shopping. This village is in a National park. You are almost guaranteed to see Keas (Alpine Parrots). Anything else would probably be a nice bonus. Don't feed the Keas. They can be very inquisitive and may attempt to open your backpack, car, or other personal belongings, in their search for food. There are three places you can get food. We ate at Arthur's Chalet Restaurant (the restaurant with our motel) - best pies. And had lunch at the Wobbly Kea. It was good, if unremarkable.