Nobody refers to our own world as “4D” or flat cartoons as “3D” though. In colloquial speech, the number before the D is the number of spatial dimensions, so “4D” is correct here.
You're absolutely correct. But notice how I used the term technically?
I just wanted to point out that time is basically a spatial dimension and we have alot of experience with 4D objects. The temporal aspect of time is entropy; that is the only difference.
Other than that the equations literally call it spacetime and treat it as the same thing.
The 4th dimension you experience in the game is literally time with the arrow of time removed.
The only difference between time and space is that entropy propogates across time but not space.