Better help can be had from an old forum question.
Original poster is: Chacha 12 Aug, 2017 @ 6:48pm

Dark Elf keyboard commands
There's no instructions for this game (at least, not on Steam...), and this may be just general RPG Maker stuff, but here's what I found:

Alt+Enter - enter/exit fullscreen
F1 - settings menu
F2 - show/hide FPS counter
F5 - double window size
F12 - reset game

I can vouch for F5 working and making it far more enjoyable to play versus default settings.

i cant set the screen on full help please

is there anyway to set the resolution?

Question the game forces me into the left top corner somehow and i cant really control the character

You can also “ alt + enter “ to change on the fly