The thing is, Entrenchment uses Impulse as installer. As such, the only kind copy that does not rely on the Impulse program for installation is one you make yourself. If you want just a backup, so that you do not have to re-download the game in the future, you can either use the archive feature in Impulse, or download entrenchment from http://anywhere.impulsedriven.com/. That will give you an executable and datafile that can be used to install entrenchment without an internet connection being required. Said executable does require Impulse being installed to function, however. Furthermore, since Entrenchment requires online activation, you will still need either a direct internet connection or access to an internet capable device in order to install the game on a new computer.