think its broke. video inside

[Niall]

Hasnt had a oil change recently has it?

Tbh, that random rattle doesnt sound to brilliant. First thing i would do is whip the plugs out and check them as others have suggested and then maybe look at the timing.
It could very well be a stuck lifter. They make a horrendous noise (just ask matt!) and it does sound like it was a snapper but with the right oil in, it generally disappears. Any history of the belt being done?