Doss box runs the games in strange asspect ratio. How can i fix this?

You can expect DosBox to run at standard 4:3 aspect ratio. If you don't like you can dig into the dosbox config files for each game (usually they bear the game name and end in .conf ).

you should change output=overlay to something like output=openglnb and aspect=true to aspect=false

Bear in mind that Dos games are designed for square screens, and will usually run at 320x200 pixels. If you stretch them they will look weird, and worsen the wider your screen is.

To have correct 4:3 aspect ratio the option must be set to "true"