Alien Swarm: Reactive Drop has many functions in it for users to customize the game.
My friend and I are both skilled with game customization. By default the game is installed on C: so create an autoexec.cfg file at C:\Program Files (x86)\Steam\steamapps\common\Alien Swarm Reactive Drop\reactivedrop\cfg
// Client UI asw_particle_count 1 developer 1 net_graphshowinterp 0 net_graph 0
This will leave the overlay off all the time. It can be commented out if you prefer to disable it for some reason.
Alien Swarm: Reactive Drop also supports keybinding. At present F9 is used to view server and player ping times etc. So I figure what not use Alt-F9 which is an alternative unused key.
// Client UI asw_particle_count 1 developer 1 net_graphshowinterp 0 net_graph 0 // Server Basics asw_marine_death_cam_slowdown 0 rd_override_allow_rotate_camera 1 asw_ignore_need_two_player_requirement 1 rd_ready_mark_override 1 rd_suggest_difficulty 0
Some of the other customizations such as disabling the death camera and slow down that disrupts play can be turned off. Also the two player requirement can be disabled too. The difficulty nag can be disabled. And the ready delay can be sped up as well for laggards.