https://www.doomworld.com/vb/doom-2016-general/86076-doom-alpha-code-strings-new-info-spoilers/
Some of these are (check the full thread for more):
>Archvile confirmed
>Spider Mastermind confirmed
>Automap confirmed
>Shitton of menus
>Game tracks kills/secrets
>Game functions in chapters, like DOOM 1
>There's 5 chapters total
>New Demon types
>"Aqua Marines, and Hell Marines"???
>Mutators for custom multiplayer matches
>One of these mutators allows Strafe Jumping
And check page 3 for weapons showcase, and another webm where the player moves around and it seems to go faster than previous previews.
Now I'll just wait for when the game'll be released.