From AMLopedia
C-Dogs is a top-down view shooter game made by some guy named Ronny. It was popular with Liam and Adam because it could be played by two players using the same keyboard. Liam originally found it while looking for free shareware games online.
The catchphrase "they do that sometimes" was spawned when one of the enemies shot his own teammate. Adam exclaimed "they do that sometimes!" In a really high voice.
This game is a sequel to Cyberdogs.