I was going to say out of Half Life (as in the 1998 original), so we're clearly thinking about much the same era :)
I think it's the slightly crispy edges where the blurred background starts, combined with the overall... flat... appearance.
Cute cat though.
I bought one of the really sturdy kind (weighs about 40kg / 88lb). Uprights are solid 100mm/4" rounds of pine, none of that hollow cardboard tube nonsense.
My XL-sized void loves to haul arse into the room and leap right from the ground to the top level (around 1.6m / 5'3" from the floor), which makes the thing rock side to side fairly precariously. He hasn't knocked it over yet, but some day I'm sure he'll come in too hot.
Also yawn