Your game sounds interesting. Good luck with it! I think mine can be described as an escape room kinda game. It takes place in an office and the objective is to go to the roof before the kaiju arrives and destroy the building. The game begins with the kaiju walking towards the building, so there is a time limit. It was going to have multiple floors to go through, but I decided to leave only one. This makes it very very short, but that's okay for me.
Sounds like an interesting idea for a time limit, do you see the monster coming closer and closer through an office window then? Or do you show the time limit in another way? I went with the medieval setting (medieval), starting as a baby dragon (small) and growing bigger after eating enough food (evolution). The end goal is to fight the human hero and eat a city.