Theoretically, ESF will work with WON2 online, as it works with CS 1.5 and Half-Life. It is much buggier than WON, though, and crashes often. But I'm not going to tell you where to get it, since that would be, as Pain states: "giving information on how to bypass Steam." And for that I can get a warning, and possibly a ban. BTW, asking how to play with WON on these forums won't get you an answer, though it is possible, but these forums don't support it. The answer you will get is "Use Steam." So don't even try it.