So after the new patch(the huge buff of boss) this is what I think of difficulty of each key boss in 1v1 when you are level 60 (boss vs player)
Crocodile Giant - not easy but doable
Scorpion King - pretty much doable
Locust Queen - pretty much doable
Tiger White - pretty much doable
Elephant Alpha - pretty much doable
Rhino King - not easy but doable
Undead Dragon - not to underestimate but still doable
Demon Spider - pretty much doable
ReptileBeast Boss - 50/50 I lose sometimes, I win sometimes, it seems its damage is even higher than Rhino King.
Giant Spider - with this one, I am struggling in 1v1, it has fast speed, long range attack, fast attack combo I can still dodge all but barely can hurt it without getting hit by it. It is much harder than any other bosses in this game.
Giant Spider Skull - same as Giant Spider
Snake Alpha - just freaking fast, and very long range attack, it just instantly hurts you whereever you are in its range.
Snake Giant - same as Snake Giant
Anyone else think Giant Spider (and Snake Alpha) is bit too strong?
(I honestly think Snake bosses are even harder than Giant Spider tho)
If anyone wanna try instantly vs these bosses try Admin Panel in Single Player