I have not been a fan of the F-35, but if this was a valid test against F-15Es, it says the F-35 is a serious aircraft, for sure.
It's hard to say.
And to add, assuming a no holds barred simulated dog fight (as opposed to the RedFor aircraft flying simulated enemy tactics) is like to see how the Lightning II stands up against not just single seat F-15s but also F/A-18A/C/Es, F-16Cs, Eurofighter Typhoons, Rafales and Gripens (assuming later mark members of the Su-27 family are unavailable).
That having been said, the real beef I have with the F-35 is that it’s been sold as a fighter rather than a very capable stealthy light strike platform. Which is what it really is.