Brokami, my brother! I was having the same problem as Rexa, unfortunately. Here's the issue in detail: The game launches, but only for a split second before closing out without an error message. I have the latest version of DirectX installed, and I've installed your ENB onto fresh versions of FeralHeart - I did the 'try different versions' solution, but to no avail. I tried high, medium, and the experimental beta ENB, all on fresh FH installs, and it still produced the same error.
And now for how I fixed it: I actually looked through and tried to find a crash log in my FeralHeart folder, and I got this
full path: C:\Let's Go\Vanilla FH\FeralHeart\
redirecting CreateDevice
initialising shader environment
D3DXCreateEffectFromFile failed
C:\Let's Go\Vanilla FH\FeralHeart\d3d9.fx(39,10): error X1507: failed to open source file: 'SweetFX_preset.txt'
It appears the crash occurs because the SweetFX_Preset.txt file is missing from the download, which after inspecting, it is. Using an old SweetFX_preset.txt from your older ENB releases fixed the crash.