itch.io

Okay. You don't need RPG maker. What you do is you doubel-click/right click on that icon that says "game" next to it. 

Then your computer should give you an option to extract it. Say yes.

Afterwards you should have a similar folder, except your the icon will change to a picture.

Does it look like this? If so you should click on the icon with the name of the game next to it. Afterward, it should give you the option to "extract", do that and it will give you a new folder. But this one should let you play the game.

Alternatively, if that doesn't work click on the zip file and select "Extract all" in the options. 

Is there inflation/growth in this game? If so whose effected and how big can they get?

Maybe some sort of sandbox mode? Where you don't have to worry about staying alive. Like either spawning individual infected or some sort of ceiling to prevent floating away, and of course invincibility.

If someone wouldn't mind awnsering how many sizes/staged do the charaters have?

I think you have to download the new version everytime.

Is their a way to manipulate the bodies of the NPCs, like the potion sellers or black smith?

Have decided what the next updates "theme" will be?

Is their growth in this game? Can our main character get bigger, and if so, how big can she get?