I was thinking about scp multiplayer since when scp:cb was version 0.1.2 to version 0.3.2 ,and will write what I was thinking:
*You can host local area network or create online server and share your IP adress.Features:
-Above player heads there is a eye icon,that shows players blink meter.It fades away slowly and then reset back to normal.This means that player blinked.(unless flickers a second when player manualy blinks)
-Eye icon will turn red when players is blinking faster and it will turn blue if player used eyedrops.
-I doesn't show sprinting icon.
-Co-op makes much easer to avoid scp-173,but still,accidents happen.
-Lights have slight chance to flicker making scp move towards nearest player.
-Chatting and voice talking system.Also the nickname.
*Text that appears on events (reporting other players what is going on,orange text is death text,white is normal):
-When player is killed by

:%playername% neck got snapped. or %playername% got hugged.
-When player is killed by

:%playername% got pulled into other dimension. or %playername% got punched in face.
-When player is killed by clockwork machine :%playername% was playing around too much. or %playername% got gearded.
-When player is killed by coffin :%playername% was watching wrong television. or %playername% couldn't look away.
-When player goes blind(red eyedrops) :%playername% used wrong eyedrops. or %playername% needs blind helping dog.
-When player hears cowbell :Something is stalking %playername%. or %playername%,say hello to scp-513.
-When player dies by mystery bottle :%playername% was too much curious. or %playername% drank some hard chemicals.
-When players smokes the joint :%playername% is gonna get trippy. or %playername% <3 drugz.
-When player enters the maintenance tunnel :%playername% explores the tunnel. or %playername% got very bad ideas.
-When player is killed by administrator :%playername% got slapped by %playernameadmin%. or %playername%
*Commands:
-/kick %playername% ;kicks the player from server.
-/ban %playername% ;bans permanently
-/sorry %playername% ;unbans banned player,deactivates punish command
-/console off,on ;turns on/off feature to player to use console cheats. [default=off]
-/op %playername% ;gives player ability to use console cheats.
-/deop %playername% ;same as above,but vice versa(takes the ability).
-/disable %scpnumber% ;disables selected scps from the server. [you can put "mtf" in %scpnumber% to disable MTF]
-/enable %scpnumber% ;same as above,but vice versa(enables disabled scps). [you can put "mtf" in %scpnumber% to enable MTF]
-/spawn %scpnumber,%itemname% at %playername%,x y z ;spawns scp or item on player or at selected coordinates
-/despawn %scpnumber%,%itemname% ;resets the starting position of scp or item
-/screw %playername% ;deletes whole player inventory and teleports it to spawn point(scp-173 containment room)
-/tele %playername%,%scpnumber% to %playername%,%scpnumber%,x y z ;teleports player,scp to another player,scp or at selected coordinates.
-/kill %playername% ;kills player instantly.
-/scare %playername% ;flicker a random scp model front of selected player
-/punish %playername% ;spawns a scp-087-B model front of the player,this scp chases player by nocliping.Kills on touch.
-/setspawnpoint %playername%,x y z ;sets the spawn point to the player or selected coordinates.
I hope this leads to ideas,because I have no idea how to make a mod for scp(other than re-texturing and changing sounds).Or even add multiplayer feature to the mod

I wish I could make it all this into my own multiplayer mod...
