While One Last Week is heavily indebted to the usual tropes of the genre (calling what's happening specifically a zombie apocalypse feels like a step too far in grounding it in the familiar), it gets a lot of things right as the kind of story it wants to be. Some clever details help it convey the weight of time passing, and the main characters are recognizable but believable archetypes representing how a person might respond to the world ending.
Though some of the exposition near the beginning is a little blunt and the story misses an opportunity to linger in the ambiguity of what precisely is going on, the character arcs considered, a fragile veneer of mundanity does not feel like an inappropriate tone to aim for. Also, I do think the game hits some successful notes of dread as it goes on; there's a harrowing tenseness to the last third or so, and the climax lands both in terms of the prose and the direction. The only thing weakening it is that it feels like the text has already worked through the central ambiguity to the point that it's nothing new here.
The stylization of the art pays off in the ending, too, and it gets a lot of mileage out of the couple of tricks it uses. I wouldn't call the rest bad to look at, either – all the little details in the backgrounds help create a simultaneous sense of verisimilitude and something being deeply wrong with the world, and the paper border comes off as a functional reflection of how sketchy the style is on the whole. Along similar lines, the sparseness of the sound design helps emphasize what's there a lot, which is particularly nice with a radio show being a central plot point.
All in all, really enjoyable. I would not have minded a slightly fresher approach to the premise (particularly in the context of this jam, since everyone apparently decided to do apocalyptic fiction), but that is no big flaw.