I had an issue where the game surface was not drawing properly when starting in fullscreen, also when switching between fullscreen and windowed where the screen was kinda streetched.
I was able to work it around by udpating the output_window and output_height to rely on view_get_wport(0) and view_get_hport(0), also udpating it on resize surfaces (for switching between fullscreen and windowed)
Aditionally my screen was all black so in the crt_apply function I replaced the with (all) to draw_surface(application_surface, 0, 0, game_width, game_height)
Btw the plugin is fantastically good and very customizable! Really good job!