The game uses OpenGL Api.
NOTE 1: If you are using an Nvidia card, you will have to rename kingpin.exe to get ReShade to load. This is because recent Nvidia drivers seem to assign kingpin.exe to a game profile and load its own OpenGL library, ignoring the custom opengl32.dll.
NOTE 2: If you want to keep kingpin.exe as it is, for instance because you want to be able to launch the game from GOG Galaxy, you can do it the hard way and edit some system settings:
https://forums.geforce.com/default/topic/1075623/geforce-drivers/is-there-a-way-to-prevent-nvidia-drivers-from-loading-its-own-opengl-library-opengl32-dll-for-a-specific-game-/post/5890182/#5890182
thanks brazzjazz
NOTE 2: If you want to keep kingpin.exe as it is, for instance because you want to be able to launch the game from GOG Galaxy, you can do it the hard way and edit some system settings: https://forums.geforce.com/default/topic/1075623/geforce-drivers/is-there-a-way-to-prevent-nvidia-drivers-from-loading-its-own-opengl-library-opengl32-dll-for-a-specific-game-/post/5890182/#5890182
NOTE: If you are using an Nvidia card, you will have to rename kingpin.exe to get ReShade to load. This is because recent Nvidia drivers seem to assign kingpin.exe to a game profile and load its own OpenGL library, ignoring the custom opengl32.dll.