Ninja Gaiden PC Port Fix
If you have a gsync/freesync high refresh rate display (ie higher than 60hz), the game will be broken and run at 35-45fps at any resolution, unless you are not focused on the window, which prevents you from playing the game.
The FIX - get in control panel and set the game to be at fixed refresh rate, without gsync, then also set your display refresh to 60hz. This seems the only way I've found to get flawless 60hz and avoid this issue. There is probably a more elegant solution.
Anyway, after the fix, since the game runs flawlessly, I'm fine enough with this shity port. I would normally never buy such a port, but, I have time off soon and I have a lot of nostalgia for Ninja Gaiden 1, so I will count myself unluckily lucky