game seemed kinda weird for me as well, i mean the curve got insanely steep after river, and in the mountain the consecutive assassin bosses were insanely hard, oneshotting my MC, had to grind quite some time to gargoyles, then the spirit wolves before the mushrooms gave me almost 30 lvls per fight so grinded there as well. dunno if that was broken or not, but without it game seemed ultra hard at moments
Enemy level scales, with a cap.
Some enemies do not have a cap listed, which can make them a problem. If you find an uncapped enemy, report it, as it is a bug.
I talked to dev and he confirmed all monsters should be level capped
I recommend going the sin route. 5 extra equipment slots and utterly ridiculous XP bonus.
Also keep on mind that level is just a meh way to get stats. Stats are what matters, and you can get stats in various ways.
(spend souls, or get the magic pills that perma boost them).
Most enemies gain more stats than you per level. which means you need to rely on such tricks. Or outlevel them. which you can easily do via sinner
Also, do not fight fair. You are of the [dark] element. use hellfire to give everyone DOT based on max HP% + blindness. use black dragon and his miasma attack to give everyone ALL the debuffs that exist in the game. effectively stunlocking themforever. And giving another DOT based on max HP%.