“sv_portal_shot_fizzles_enemy_portals” = “0″ game – (PORTALMP) Your portal shots will fizzle any enemy player portals that they hit
“sv_portal_shot_push” = “-1″ game – (PORTALMP) Amount of force to apply to a player if your shot hits them. <= 0 pas
Apparently, there was the possibility of having enemy players in multiplayer.
Not that the news is totally surprising - Erik Wolpaw actually discussed such a feature in 2010 during the Summer: Along with co-op, [we had] the idea of sort of a competitive Portal multiplayer. We went down that path, actually, for a little while and had something up and running — the best way to describe it is sort of speedball meets Portal. You know, a sports analog. And it quickly became apparent that while it’s fun for about two seconds to drop portals under people and things like that, it quickly just devolves into pure chaos. It lost a lot of the stuff that was really entertaining about Portal, which was puzzle-solving. Cooperative puzzle-solving was just a much more rewarding path.
There may not be any versus multiplayer in Portal 2, but you can bet some modders will take what Valve half-started and run with it.