For those getting the full screen error,
View attachment 1445526
Make sure your monitor resolution is
1920x1080 or below. This is due to custom window size written the the script of the game and it is hard coded for only a max res of 1080p.
you can go fullscreen by pressing F5 actually (although there will be a very
slight stretch in the image vertically if you are using a standard 16:9 monitor) for this particular game, pressing Alt + Enter WILL NOT GO FULLSCREEN anyway.
Seems like there is quite a few rpgm vx ace games which uses custom resolution this past few uploads on this site, Honestly not sure why the creator made the CG in such a weird resolution and aspect ratio...
Rpgm MV would not have all this issues as it has adaptive scaling and built in custom resolution support though.