Ive tried changing the graphics setup, no luck there. Even with the dosboxdeus.conf file, no dice.

Everytime it starts, it goes windowed and if I try "alt+enter" it will either not go fullscreen or just stay on a black screen.

EDIT: Ok, Im having problem with both games. None of them will start fullscreen.

Running almost any game, from GOG , on HDMI will make them not start or have problems. Change your output.