There are three different categories of online dependency:<br>1. Just for DRM and updates. Tranformed into forever-offline version relatively easily.<br>2. Part of gameplay mechanics are transferred to remote server. For example, "shops". Some of them can be removed without any sorrow, some can be emulated with DIY server.<br>3. Single player game is in fact played on remote server. Not in streaming sense, but, for example, monster drops are stored on server, while monster textures are on local PC. This is the case when game dies with remote server. Theoretically, it is possible to make emulator also in this case, but not every information can be extracted or guessed, which will result in similar, but in fact different game.