Imagine a dark room were you just see some blinking lights and hear technical sounds (beeps and boops).
Then a concussion in an area nearby, which sets an alarm of, so the room gets lightened by yellow lights (still pretty dark).
It's a laboratory just like this:
but with a twist: Inside the glass isn't a Metroid, but Mewtwo (just like in the first Pokemon movie).
Mewtwo awakens because of the eruption,
looks around, then a big thing crashes trough the ceiling, burning its way through it with fire. Smoke and dust all over the place, yellow glowing eyes shining trough it.
A dark figure in the shadows, nearing the container Mewtwo's in. (Mewtwo is a synonym for the Metroid, Ridley wants to use it's power as a weapon). Mewtwo breaks out of the glass:
Smoke get's blown away by the shockwave Mewtwo creates,
Ridley's visible for the first time:
Fight begins. Imagine it as epic as you wish. However, Ridley gets the edge on Mewtwo,
Mewtwo is still weakened and hasn't regained it's full potential yet. That's when Pikachu makes an
appereance out of nowhere. Pikachu stands protective in front of Mewtwo
(Homage to Brawl's cutscene, but this time Samus isn't the one who has to be protected)
Ridley wants to attack Pikachu,
but gets distracted by yet another fighter that enters the fighting area:
Ridley quickly forgets about Pikachu, wants to kill Samus once and for all. Samus adopts to a fighting stance, Ridley rushes on her.
"Ridley... Time to go!" Gameplay footage follows to show Ridley's moves. Footage ends with a climax. Both Samus and Ridley use their Finalsmash. Footage is cut in a way that it looks like they'd use it at the same time. Ultimate hype generated.