What you're showing is extremely familiar stuff, though:
1. First person, I immediately understand that.
2. Fight guys, sure.
3. Okay, you're picking stuff up and killing guys.
4. An alarm went off, I know what that means.
5. You're picking up a bunch of various objects, I guess that is the loot.
And that's pretty much what I took away from it. The TLDR seems to be "you sneak around and steal stuff, and kill people from behind." That's fine, but that's like trying to compare an explanation of Memento or Inception to an explanation of Speed. The two require vastly different approaches. 
I'm more getting across the point that you don't have to explain everything you are showing as long as the general idea behind it is clear.
To come closer to the genre in question, here's the Crusader Kings II trailer:
https://www.youtube.com/watch?v=qzkVTDfxIUICrusader Kings II is a strategy game with lots of complicated menus, and all sorts of UI elements and menus are popping up here without much detailed explanation. There's narration, but it doesn't deal that directly with what's going on UI-wise, instead it's conveying the general idea of what's going on.
The audience perhaps doesn't know what screen or menu does what. They do understand that "you play as a king, your fending off an invasion, stuff is happening". They do understand that the menus and tools they are being shown are part of that, so in general they understand what they are for in the end.
If they need detail they can ask or research later, but the important part is that they become interested in the game.
