You can use the command line parameter "-window", "-sw", "-startwindowed", or "-windowed".
Chat with our AI personalities
change the line windowed = 0 to windowed = 1 in medieval2.preference.cfg. If you want to play with borderless windowed mode, add borderles_window=true below.
There is something called Decay on the first half-life where you play as two women during the incident. There is also a half-life 2: deathmatch, and that's more or less it. There is Half-Life Deathmatch and Half-Life Deathmatch: Source. You can also download a mod, "Sven Co-op", which allows you to play the Half-Life story with other players.
Gordon Freeman
By co-op you mean mulitplayer. Yes. Half-Life 2: Deathmatch is only on PC.
Download the mode or change the play mode to creative.