Apart from its god awful title, which sticks in my brain like a comedically shaped object in the gullet of a cartoon ostrich every time I read it (seriously, 'atom' isn’t a fucking adjective, is it? Zombie Atom Smasher seems like it would make more sense, but only barely), Atom Zombie Smasher was an extremely fun, extremely stressful little game. The premise was a distillation of the trend for undead tactical “realism” that emerged from Max Brooks’ Zombie Survival Guide in the early 2000s: it was your job to evacuate a sequence of randomised top-down city maps, rescuing single-pixel civilians with helicopters, while keeping them safe from single-pixel zombies using a meagre selection of tools such as snipers, artillery and infantry.
The thing was, you were never, ever equipped for the job. The infection modelling was so punishing that swathes of civilians would collapse into undeath after the slightest brush with a zombie, while the resources on hand were always woefully inadequate to beat back the deadoes. It was so utterly unpitying, it makes a renowned digital miser like Frostpunk seem as generous as a roomful of pissed uncles in comparison.
The relentless shortfall was where the fun was, however. Since you were almost always losing (often purely through poor luck) when you did manage to pull off a decent evacuation, you felt messianic. So many games try so hard to convey the atmosphere of a last-ditch struggle against an overwhelming foe - see the XCOM franchise, for example - but are let down by the arguably reasonable need to offer players a sense of fairness and progression. Atom Zombie Smasher didn’t care a bit for that: it just smashed you, again and again, like an atom, or perhaps a zombie.