Normally SCP games are horror themed, so I’d suggest making it less bright and more eerie. For example, the ‘GATE A’ could flicker between off and on, along with some of the other light sources in the build. Like others have said, the roof needs some work, maybe the floor too. The gate seems really plain to me, I’d suggest maybe splitting it into two pieces and adding some form of design to it.
In my opinion as an SCP Genre builder, this is okay but it’s a bit outdated, it reminds me of 2018 SCPF hallway. However, I do highly recommend to take a look at some famous SCPF games, such as Area 19, Site Phoneix, Area 27, Blacksite zeta, SCP Roleplay, Site 39, Site 19. The ceiling is kinda too dark, the material should be metal for the SCI-FI theme, try to add some little details more than this.
The door/gate also looks too flat, I mean it supposed to be a gate/door more than just a flattened part with diamond plate material. Some of the gaps are also should be fixed.
This is only from my opinion as an SCP genre builder.