Pretty solid concept. I did run into an issue I think regarding the procedural generation. 1 of the roads spawned too close to another, resulting people getting eaten by the dragon on that other road. (My peeps were trapped in that city for basically that run.)
I do like the puzzle aspect of the dragons trying to eat you, while also clearing snow, making your guys moving faster. The once confusing aspect is that the people appear to be safe while they're still in the cities themselves. (I was under the impression that the idea was to evacuate the cities before the dragon comes.)