No, I should be the one thanking you.
You see, I have two projects on Godot right now, but this one is the only one that actually works with multiple characters. Thanks to your input I was able to see a memory leak situation that I'm already working to fix and release here the fix right away, but essentially the Characters were not being "removed". This would essentially create a situation where, whenever I hide a character his "node" still exists in the scene, forever.
This was fixed, and I already checked that the memory stays stable now.
However, Godot will still slowly build up RAM just like any other game, so as you play the memory will get more usage because that's just how Windows works, but I already made sure into the game that these resources won't be recreating themselves forever. :) An update will be added here shortly so try to download the game again in a few hours.
Thank you for your input again, and for giving our project a shot. :3