this is clearly a resolution problem. i know 3 way for it.
1 - you play game with resolution not compatible to your screen (i dont think)
2 - the custom UI is resized wrong (too big , out of limit of renpy)
3 - the Ui is moved in setting of game (bad scripting from dev) . but i doubt that as only you have this apparently
N°2 would be the reason, but if only you have this, then its mostly the number 1. check wich resolution you play the game compared to your screen.
also, check if you play fullscreen or not. seems like the game UI is set for full screen and you play windowed.