Curious what this "Inventory System" highlighted in the works via steam some updates ago will consist of, to memory the only [and I mean ONLY] items you carry on your person is ammo, weapons and keycards per the mission you're on.
You'll also find NPC-related items such as medkit or supplies which I think total 5 such instances across the entire game.
It would be amazing to have either a mini-map, a better UI to denote what you can interact with [had to use youtube to advance in certain areas because there were certain things you needed to interact with that blended with the rest of the walls/environment] from a distance... or both, both is good.