I shall provide my two cents.
There was a twitter post with a dev saying that the trailer was supremely close to the actual game.
Four characters were revealed for being in the game:
Scorpion
Raiden
Shao Khan
...and a mysterious, time-influenced character. She could be a big bad, an elder god, or just another character.
Multiple weapons were showcased:
The Wakizashi and Katana combo and Kunai were Scorpion's weapons.
The Guandao/Naginata and Gun/Bo with metal tip were Raiden's. The Guandao/Naginata could be either Raiden's or an interactable, epending on which way it can go.
Shao Khan of course had his 100 lb Warhammer, ready to smash anything in his path.
Then there were the images from Steam. These images interest me a ton.
The images are an amazing example of what the game is going to look like. They seem to have gone with a much more saturated game compared to MKX. Raiden has all sorts of different colors in his color scheme, including dark turquoise, white, gold and black. Scorpion is the same, he seems to have a brighter scheme, with some crimson and white as well.Then we have an alternate costume for Scorpion with a more classic look, ditching the pauldrons and extra armor.
Then there is an image of Raiden performing either a reverse version of Quan Chi's trance, or the beginning frames of a regular trance of his own on Scorpion. Scorpion is in this 'alternate' costume, with his entire being surrounded by red lightning. Including his kunai. Upon further inspection, the image with Raiden doing a Yun-style Zesshou Hohou, Scorpion has a kunai in his hand as well, and he is in his 'regular' costume. Does this mean that he will always hava a kunai in his hand? Also, what looks like a cinematic of some sort, 'alternate' Scorpion has regular, brown iris eyes,as opposed to the white eyes he has in the 'regular' costume. Does this mean that the retro-looking costume we say in the trailer is a third costume? I don't know.