Quite unique perspective and cinematic ideas over the simple "person after a breakup dealing with the subsequent emotions and their own idea of self" trope, that shows tho that with ideas and a clear view you can still spin it a gave it a fresh look.
The characters are simply described but I feel that's not really the point of the movie: you see things as an observer, as Ben does during his [spoiler] freezing time moments [/spoiler] and you are given time to put your own experiences into what he's gently and carefully watching in others.
The tone is light and the funny moments are indeed funny and not forced, secondary characters create a little and personal world feeling, relegated to the supermarket and Ben's inner world.
Some lines in the script feel a little pretentious, but they're missteps over an overall lack of pretentiousness, of desire to take themselves too seriously or to play with the viewer's feelings when watching such a movie - creating romantic moments that feel fakish or putting cheap jokes. This picture doesn't do it in a refreshing way, chemistry between the 2 leads is nice and the general feeling is relaxing, like watching into a tiny window of world.

I find these smaller English productions (as Starters for 10, for example) extremely enjoyable and with a heart and creative ideas that I often see lacking in the correspondent US indie ones (that are generally way better at that than big studio coms).
I had never heard of Cashback, glad I picked it up tonight tho!