Launch fraps.
Go to the movies tab.
Set up your preferences and Video Capture key(the button you start recording with)
minimize the window, do not close it, start up your feralheart.
Press your video capture key inside of the game, when the fps counter in the corner of the screen turns red, it's recording, press the video capture key again to stop it.
To check your video, go to the folder that the videos are saved to, if you go back to the video tab in fraps it should show you where on the computer the clips are saved to.
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Special note:
Fraps can be very demanding on some computers, especially if you run something like FeralHeart. You might need to change your capture settings to half size, and something like 25fps max if your computer is struggling keeping up with everything.