I'm playing on Expert mode.
I'm purposefully have not upgraded any health buffs except one extra health bar. No manual healing. I have to hunt and find meat if I wanna heal myself! Which makes things much more exciting!
I have not really upgraded my guts bag or arrow quiver. Have a max of 16 arrows and guts bag holds 12 meat. If you upgrade too much it would just make scavenging, hunting and looting redundant IMO.
I also turn the mini map off completely!
But that's what I like about Far Cry, it gives you options to tailor the experience to your liking.
I knew going into this game that I wanted the most hardcore survival experience possible.
Expert mode, I personally find not too difficult, but more importantly it's not too easy! For me it's the only way to play the game.