4: Earthsiege 2
Before there was Tribes, before there was Starsiege, there was Earthsiege, Sierra’s hardcore mech simulation game that was heavily inspired by the Battletech board game and connected Mechwarrior universe, but didn’t have any official license. The not-so-cheap-but-also-not-official knock off proved to be quite the success in the long run. Earthsiege 2 featured customizable mechs, soft fail states for missions, salvagable enemy mechs and a for the time highly detailed terrain.