The guy in the first video just kind of casually drops that Exhaustion has been significantly changed (which Jeremy Crawford takes in stride, but I’m guessing he wasn’t actually supposed to say). That’s interesting because in the most recent UAs it had disappeared from the rules glossary, which according to what we were told about how to playtest the UA content meant we should continue using the 2014 version. But apparently it is some sort of cumulative penalty, the effects of which increase predictably with each additional level of Exhaustion to make it easier to remember, rather than each level having a unique effect. But, there are still 6 levels in total and you still die if you accumulate 6 levels. Interesting.