Spiders get huge for some reasons
|Spiders grow to unlimited sizes in a series of scenarios|
The spiders must be friendly and not hurt anyone even if it no sense
If you don't like spiders getting super big learn to love giant spiders (and their normals sized cousins) and then come back
Keep choice chapters to a minimum, after the scenario is chosen get straight to it and give an exit choice, especially please avoid chains of choice chapters mid scenario, these things break the narrative of the story making it much less enjoyable to read and often kill a path. I would like as high a percentage of the chapters to have story in them as possible.
Present choices that give flexiblity about exactly what happens in the next chapter. E.g. when the spider first turns up rather then several chapters determining its exact size give options like 1. you hear rustling in the bushes (smaller spider) and 2. You hear a steady series of of mild earthquakes (big spider). Gender and whether your spider or a human (or whatever) should usually be decided in the first chapter of the scenario with different start option for changing those things.
Non spider things can grow too as long as the story stays focused on spiders getting big
Whilst the spiders must be friendly anything that isn't a spider can be mean, its a lot easier to be good if there are some bad guys to stop.
Any additions are welcome, creativity is valued more then polish