I still haven't even completed it on expert, but I feel like the weapon balance is off. expert makes the uzi more useful, but in terms of the 3 "advanced" guns (I'll just call them that because they're upgrades to the 2 starting primary guns) the best one is easily the assault rifle. The auto shotgun is barely better than the regular shotgun. The hunting rifle is good, but it has a lot lower amount of ammo than the assault rifle, which is pretty deadly at long ranges, has twice as much stock ammo, and over 3x the clip size.
I just hope the other guns in the game will be better/different. I don't necessarily mean wildly different than the shotgun, full auto, or semi-auto rifle setup they have now, just that they should make guns that offer some different playstyles.