so you seek Critique, I try to add some and hopeful help you.
The concept is great and I like how you delimit the time portal from the museum.
- change the perspective, keep it like your the visitor - your camera could be on the height of a person -like 1,80 m above the floor.
- your stone arch is would collapse, just google keystone.
- the shadow behind the left column doesn’t make sense, because I can’t see a light source (spotlight)
- change the material for your stages, the patterns are to similar
- why are the lights left and right different colors?
hope it helps, good luck.