Very small and very limited selection, but they stock the basics and its conveniently located on the main highway. Parking is limited and on the main highway right before the speed increase so a little hazardous if you are exiting a vehicle with small children. Not terribly wheelchair friendly.
It's a small, old store with a rather limited selection - but Hawarden is a tiny rural town so they're actually very lucky to have a supermarket! Gotta give it props for the convenience as it probably serves a few other nearby towns too (Waikari, Pyramid Valley, Hurunui, Balmoral, Weka Pass etc) remember 4 Square are locally owned and run so it's a good place to buy.