I like the idea! I think the heat mechanic is more of an annoyance than a useful game mechanic though. In a game with no time pressure there is no point to making the player stop and wait for the heat to go down. Maybe time pressure was part of the idea but you didn't have time? that might have given more weight to your decisions of what to prioritize and you might have built levels around giving the player a decision for what to do when. A simple optimization game. As it stands I think it doesn't have enough meaningful actions. But I like the idea, and I like the art. Nice job.