dont worry, its nothing like the crysis 2 overhaul. it has something to do with hacking crysis's cvar to enhance settings. i still get steady frames on whateveer he configured 'ultra' to be (press '8', i believe).
this is what i downloaded; if it switches your language to espanol as it did mine, its an easy fix (just google, i think the file to edit is system.cfg but not sure).
O Hide HUD (Maybe you want to take some beautiful screenshots)
P Show HUD (Maybe you want to locate enemies after taking screenshots
I Modify weapon FOV (Crysis 3 resets weapon FOV after every respawn)
6 Reload low quality preset 7
Reload recommended quality preset
8 Reload ultra quality preset
9 Activate normal Depth of field
0 Activate ultra Depth of field (Bokeh filter in far distance but no weapon DOF and no radial DOF while aimimg) - See more at: http://maldotex.blogspot.com/2013/02/hyperthreading-and-real-custom-graphics.html#sthash.4Ool9wQa.dpuf