I just typed out a few notes during the showcase so I will put them here for discussion.

• There are over 1000 world. These are procedurally generated but have handcrafted content placed randomly on them.
• Every you see exists and all planetary objects can be visited.
• Illumination is changing based on the atmosphere and the sun type/proximity.
• Animation system and combat system has been reworked from the ground up.
• You can play in 1st or 3rd person.
• Resources exist and are collectable
• You can find enemy camps on planets and/or other random things/locations.
• You can fast travel to your ship.
• You can have companions that aid you on the ship or on ground.
• Visual style for the tech was called by devs as Nasa-Punk as in advanced but worn
• You can choose landing spots on a planet or fast travel to an existing one.
• You jump drive to other systems and can upgrade drive for longer jumps.
• New Atlantis is the biggest city Bethesda ever created. There are more cities:
• Akila city: Western style. Looked like RDR2.
• Cydonia city: Mining city built for resources.
• Neon: Known as Pleasure city. Cyberpunk style.
• There is a mythical group called Constellation. They are the last explorers of humanity and are looking for answers to long lasting humanity's questions. Your main story revolves around them I think.
• Character creation is vastly improved and it's extensive. Mocap used for the making.
• You choose one of 40 (employee) presets and then put more details from there.
• You choose your background and skills. Chef was an example. Your skills affect interactions in the game.
• You can have up to 3 traits and each has pros and cons.
• You get 1 skill per level and you can rank up skills.
• 5 skill trees with 4 ranks per skill. Jetpack, mind-control and Neurostrikes(heavy strikes) shown. Great build diversity.
• They studied data from NASA to strike balance between realism and fun.
• There is dogfighting in space
• Ships are highly customizable and upgradable down to rearranging modules around.
• Can hire crew members with different skills
• Ship has a power allocation system(think of an Equalizer style thingie). You can reallocate power according to situation. Shields and weapons for combat or engine for escaping, etc.
• There's a trait that lets you target specific subsystems on an enemy ship.
• You can destroy ships and loot them or board them and capture them for your fleet.
• You can commit piracy on friendly ships.
• You can build a outpost and produce resources from animals.
• You can build outposts, assign companions to them and keep producing resources. You can decorate outposts and live there.
• Guns are highly customizable down to type of ammo. Melee weapons exist. Miniguns shown.
• Gravity changes with each planet.
• Firing in 0g can push you back.
• Photo mode exists.

Please feel free to add any details I missed.

edit: Here is the full showcase(45 minutes) for people who want to watch it.