You definitely have room in this space to add more seats. Typically, home theaters are designed with different floor levels so that you can have multiple rows of seating and be able to see over the seats in front of you.

It might also be fun to create a bar area where you can have snacks and a beverage fridge.

I would look for some black electrical outlets to replace the white ones. They pop out quite a lot right now.
I agree with adding a console under the screen, as well as adding a bar area.
I'd recommend finding some rustic wooden pieces to match the wood door and trim in the room!
This room looks great so far, just a little too minimal. Maybe look for some vintage art pieces or posters. If you go with posters be sure to frame them with slim frames (either with a flat black finish, or a wooden frame to match the other wood details)