Try this, extract the attached zip file then put the Bct.Sizer.exe in the folder where the game executable is then run the Bct.Sizer.exe, it will launch the game, after that you just need to right click inside the window and change the Zoom (window size), I suggest also fiddling with the Scaling for better quality. (I forgot from which thread in this forum I got the exe, maybe someone else can link it)
I'm sorry, I fixed everything myself. Who has the same problem on joiplay. Here is the file.
(upload the json file from the archive to the game folder.)