After a few minutes in game, the FPS drops significantly. (2-4)
This also happens when I load a new mission, reload the mission, restart a mission etc. I get a severe drop in Performance.

CPU utilization drops below 10%, FPS drops to 2-4 frames per second.

I have to restart the game every time I want to go to a new/next mission.

Also, the Taskbar "icon" pops up when I launch the game but, disappears right before the game goes fullscreen. (only the launcher remains on the taskbar)