~Check for duplicate or numbered particle files. These normally end like _01, _02, etc. If you do happen to find any of these, either delete or remove them from the FH folder. You don't have to completely erase them from your computer, just make sure they're no longer a part of FeralHeart. This is usually the case.
~Try changing the rendering system options (If it doesn't crash before they open)
~Maybe try reinstalling the game. This won't affect any of your game data, but save any modifications or downloads first if necessary.