Fullscreen stretches graphics?

[Denisowator]

I've been looking around everywhere, and the only things I can find are super complicated and long conversations about how the fullscreen option changes the window to fit the screen's resolution.

I'm running the fullscreen on a 16:9 (1080x1920) monitor.

How can I stop the graphics stretching, and it staying pixel perfect like without fullscreen?

 

[Andar]

whenever a game is set to a different aspect ratio than the monitor, going fullscreen will stretch the display. That is a fact on 2D pictures.
Ace is based on 4:3 as a default, and has a maximum screen size of 640x480
So the only way to get that without stretching is to set the game screen size to 640x360.

That will require several changes in the menu screens because the display is smaller than default, but that is the only 16:9 display rate available for Ace.