The background graphics of the game have a resolution of 1024x768. That cannot be changed. Therefore the game was created to be only run with 1024x768.
With the german disc version there are two .exe files in the installation folder. "mos.exe" directly starts the game. "moslaunch.exe" starts a small launch tool. This launch tool has a submenu "Hardwareeinstellungen" (hardware settings) where you can switch the antialiasing setting between off, 2x and 4x. With 4x the charackters has a much less edgy appearance.
If you're running the game on a widescreen display and the graphics seems to be stretched, then you probably haven't set the scaling options in your video drivers in a way to handle lower resolutions of older games. Look in the video driver settings (NVidia Control panel, AMD Radeon settings, AMD Catalyst Control Center, etc.) for scaling options and make sure that scaling is to be performed on the GPU, that game scaling settings are overruled and that keeping aspect ratio is active.
The Moment of Silence is a DirectX 8 game. There are some tools out there that give older games with DirectX 8 some features that they normally don't have (often experimental). I've tried two of these tools.
1.
dgVoodoo2 This tools works for me (you have to copy the files from the 'MS' subfolder to the Moment of Silence installation folder to make it work / delete theses files again to not use the tool any longer). Choose 'Full Screen' (Windowed does not work) and 'Stretched, keep Aspect Ratio' for 'Scaling mode' in the 'General' section. In the 'DirectX' section choose '8x' for 'Antialiasing (MSAA)'.
If you choose 'Max ISF' at 'Resolution' the game renders using 1024x768 (or a resolution with an integer scale factor) with 8x MSAA for the characters and is scaled up to your desktop resolution heigth while keeping the aspect ratio. In my opinion the game looks best this way.
If you choose 'Max' at 'Resolution' the game renders using a 4:3 resolution with the heigth of your desktop resolution with 8x MSAA for the characters. Because of the higher resolution the characters may look a tad better but the 2D graphics show slight scaling artifacts.
2.
DxWnd This tools also works for me. If you add the 'mos.exe', enter 50 for 'X' & 'Y', 1024 for 'W', 768 for 'H' at 'Window initial position & size' in the 'Main' section and choose 'DirectX8' for 'DirectX Version Hook' in the 'DirectX' section, the game runs in a window.