This game, like most Scringle Engine 3 games, does not support widescreen, and instead crops the 4:3 image to a 16:9 ratio. This can be fixed with Jambo's Game Tool, although this will disable the "Advanced Features" video option, which will remove reflections from puddles and mirrors.
To fix the immediate crash when starting the cutscene on level 3, download GregFix.dll from the GregUtils website (no link provided - Greg will send DMCA takedowns to any websites besides Google that provide his website's URL) and drop it in your system32 folder. Run the game with administrator privileges twice, letting it crash both times, then start it normally. This is confirmed to work on December 2022 through April 2023 builds of Windows 10.