Ideas to fill up the space?

[xxxxxxxxxxxxxxxx]

Share some friendly, poor or constructive criticism.

The floor in the middle looks a bit like a disco dancefloor I think it's more because of the little spots of light on it though, not so much because of the texture.

I also think you should do something to make the ceiling more interesting, as right now it's just this huge flat plane which looks kinda unrealistic. Maybe you could make creative use of welders or something to create an effect like this?