Okay so I'm planning to make a map with a new idea, this idea entails

Therefore, I need to know a console command to edit movement speed in portal. Anyone?

I think it will be either hl2_normspeed or hl2_walkspeed. Not sure which though, (I'm assuming there won't have been an extra command made specifically for Portal).

There is an entity called "player_speedmod" put on in your map and give him an input of ModifySpeed, 1 is normal speed i think, while lower is slower.

Edit - Ok I just found out that you can actually disable the player portal gun from shooting (suppress attack in flags) until you set the speed to 1 again, Thats gives me some awesome puzzle ideas.