After playing the demo, I think it is much more like 2016 than Eternal. I'd say its like Doom+Ghost Runner. Melee kills will give a bit of health back, while the Core grenade you can rip out of mobs will drop ammo when used to kill stuff. The Core can also consumed to get a mega punch that will break armored mobs.
Very active combat like 2016 Doom, with the fast parkour elements in Ghost Runner. You can pick up currency while going through a mission and spend it at a vending machine in the mission to upgrade the guns, which require kills to unlock the upgrades to purchase. There is also a skill tree, which looks like it will be pretty fun to fill out.
Game was 17g on Steam, and ran super smooth with settings at High / DLSS Quality with a 5070ti. Environments are nice, but is all linear missions, start at Point A and get to Point B with some enemies along the way, plus arena wave-based encounters to move on to the next mission (in the demo at least). I expected the game to feel a bit cheap, but the demo is pretty solid. Was fun.