This is probably something that should be in developer request but I feel like for something like this it shouldn't and should just have some opinions on it first.
What is it?
It's a gamemode based on SCP - Containment Breach.
Why make this gamemode when there's already a existing one?
The original breach gamemode is not well structure from what I've heard. And literally adding anything to the gamemode or server is just a cluster fuck for us all and can even break the server. So I feel like starting making one from scratch will be best. Either that or attempt to actually fix the existing gamemode and add the changes. (Which is chaotic.)
Why not ask Duc or Haxray to implement your ideas to the existing breach server?
There is so much content on the server, it's almost impossible to undo them all. And no one wants to undo them all. And it'll most likely break the server.
What will be the difference between the two?
Not much really. They're really similar. A round starts, people spawn, one of the roles attempts to complete their goals then finally new round starts and repeat. The only difference I'll say there will be is gameplay. It'll be like realism. No hud (crosshair, healthbar, etc.), bleeding out effect, etc.
Roles and Goals
Class D - You're an expendable prisoner on the site. Your goal is to escape. You start with nothing to defend yourself.
Researcher - You're a staff member of the site. You must escape the facility or be escorted by Security Guards/NTF.
Security Guard - You're the guard of the site. You have to dive deep into hell (the facility) and save researchers, execute Class D, and either kill/contain SCPs.
Nine-Tailed Fox - You're the backup just in case of the Security Guards fail.
Chaos Insurgency - You're a rival of the SCP Foundation. Your goal is to capture Class D and certain SCPs. Kill everyone and everything else.
SCP - Kill everyone except other SCPs.
Items and their uses:
Keycards - Keycards are needed to open certain doors. You can find keycards with levels 1-5 and keycard omni.
Radio - With a radio you can communicate with other people from long distances.
Crowbar - With a crowbar you can destroy windows or defend from enemies.
Firearms - Assault rifles, submachine guns, handguns. With these you will be efficient in your goal.
Eyedrops - Eyedrops are very useful with SCP-173, if you use them you won't blink for 5 seconds.
Medkit - Medkit is useful when you are injured or your teammate is injured. You can heal yourself by clicking LMB and heal others by clicking RMB.
NVG - Night Vision Goggles are used to see SCP-966 or to make the vision brighter.
Armors - Armors modify the amount of damage you take but they make you slower.
Gasmask - Gasmasks are used to circumvent the effects of gas in some areas around the map.