JLS singing "we're the bad boys always catching your eye" — it's 'Bad Boys' but different, sung by JLS.
JLS THEN singing "we're the ones to make it beat again" — it's 'Bad Boys' but with 'Beat Again' inside it. The whole thing is a jamboree of intertextuality.
Marvin accompanying "your eye" by pointing at the audience then his actual eye.
The bits where it looks like JLS and Alexandra are a proper mixed-sex band of the variety popular in the late-1990s.
The arm-foldy wobbly-around dance move thing.
The bit at one minute twenty five when the dancers start skipping on and you think "HANG ON THERE ARE GOING TO BE A MILLION DANCERS ON THE STAGE AND IT WILL BE LITERALLY ABOVE AVERAGE".
The bit where there are a million dancers on the stage and it is literally above average.
Interesting Marvin pantaloon action.
Oritse yelling "HERE WE GO".
The breakdown bit.
The fact that it's a medley. A MEDLEY!
The amazing bit where Alexandra deliberately forgets to mime the last line of her own song.
"Put your hands up" being accompanied by hands being 'put up'.
The conspicuous absence of that other key player in the three-legged stool of the 2008 X Factor final: Eoghan Quigg.
The entire thing being flanked by two amazing Christmas trees.
The final, deliberately pathetic 'pft' of six cut-price fireworks, a conscious reference to the fact that the only pyrotechnic display capable of reflecting the lifechanging immenseness of this light entertainment monolith would be THE ENTIRE STAGE BEING BLOWN UP KILLING EVERYONE ON IT.