You know what Doom is. You are reading about E3 coverage on a gaming website. Don't pretend that you don't know what Doom is. For most PC FPS fans, Doom is going to be some of the biggest news of E3.
Built on the idtech 6 (or the idtech 666) engine, Doom will be trying to bring back the feel of the original while adding some newer feature to make the game a bit more modern.
Doom will be keeping its traditional story of "Demons are trying to kill everything, kill them back," and bringing back its high speed and intense combat. From what I saw in the gameplay trailer, the combat is going to keep that fast paced run and gun feel. They've also added not only a jump, but a double jump in order to add more height to the combat while allowing players to run circles around the demons.
Other things of note in the trailer: Finishers have been added and are extremely brutal. The chainsaw has a kill animation that locks the player in place unlike the original. Many of the sound assets are the same, such as the doors and shotguns. Finally, the plasma gun seems to have gotten nerfed a bit. Either that or the demons absorb more damage before dying.
The combat in the trailer seems much slower than classic Doom, as if it was built for consoles. Doomguy turns slower, there is a targeting reticle and weapons selection wheel that slows time and looks like it was built with thumb sticks in mind.
Multiplayer will be arena style, with freeze tag, domination and capture the flag. The multiplayer harkens back to fast paced Quake style multiplayer deathmatches, with all its glorious high flying jumps and fragging. Other confirmed multiplayer types include a horde mode and 4 player free for all. Another huge announcement was Doom Snapmap.
Snapmap is a custom map maker where players will be able to build their own maps to play and share. The system will allow players to snap new rooms onto the maps and then go into first person mode and add individual objects. This will be powered by their new client, Bethesda.net.
Doom has been announced Spring 2016.