Hi! Thanks for your replying! Yep,its not Renpy engine. It was created on Gideros.
About the short story - yes, we decided not to take big planks to be sure to meet the deadline. I'm very glad that we were able to create a good impression of the game!
This is not my first game in the visual novel genre made on Gideros. In the future I plan to make my own visual novels engine, considering what RenPy lacks. But actually, I've never used RenPy yet and have no idea what it looks like. lol