Just small things that i think should be added.

#1
I think you should be able to combine the gas mask with the night vision goggles like the MTF. Not only will let you see better with the gas mask, it will save you a slot in your inventory. Another thing that I think should be added is when you have a key card in your inventory, you don't need to select it to open doors that require key cards. Same thing should go for SCP-860. (also how do you get to the entrance zone? I can't find the switch that deactivates the lockdown.)

If these things are added, it'll make the game go slightly faster.