You can see what level Ivey is on with the hand against Paul Jackson. Pretty incredible stuff when you accept the fact it's not just cock waving.
without wanting to take anything away from Ivey, that's barely a "level 3" hand imo, they are both playing "lets rep absolutely nothing" but obviously HU for a milly it's pretty boss, I think it's way cooler if Ivey has KQ and call/calls after the flop however many bets it is.
these levels business is very misleading, because everyone, no matter how good at cards you are is capable of some really good plays, I'm going to say by accident for simplicity but it isn't an accident, it's a level of un-concious knowledge that a player has learnt without really knowing that they've learnt it. You will often see a percieved weaker recreational player on a table, offering post-hand analysis and explaining a concept that is actually quite advanced, allbeit simply, what this is is that there enthusiasm for the game and enjoyment of it has forced their brain to soak some information up and then to apply it - this is the first step of improving basically.
As you start to improve, or "level up" as it were there are basic "levels" which Jared Trendler talks about in his book, these "levels" are
Unconscious Incompetence - You don't know what you don't know, complete beginner.
Conscious Incompetence - You've become conscious of what you don't know, you begin to understand where and how you need to improve.
Conscious Competence - After countless hours of study you become skilled/have had enough experience to gain skill. You need to think about what you've learned...otherwise you return to being incompetent.
Unconscious Competence - At this level you've learned something so well that it is now totally automatic and requires no thinking. In poker this could be anything from folding 23o utg to understanding why someone is exploitable when they open x amount of hands and cbet y board with z frequency. In the book he refers to this as "The Holy Grail of Learning".
Everyone is capable of anything at a poker table, so you need to respect your opponents all the time - giving people a little too much credit, speshly live, will always be better than under-estimating them.