Loose panel???? Sounds pretty normal for a diesel, but I'm guessing yours isn't a diesel?
Noisy/sticky valve perhaps. Definitely sounds like it's coming from the top end of the motor. Does the ticking noise increase in frequency when the engine revs are increased, or does it stay constant? If this is engine related (increases with revs) then I would start with an oil change, perhaps introducing an additive for sticking valves, running the car for a say 100 miles, then flush out and do again. Pretty hard to diagnose from a short video, but sure sounds like a valve to me.