What games are similar to Empires Mod?
A similar ancestor mod from Half-Life 1 is Natural Selection. Like Empires Mod, NS has building and a very strategical play style. However, its theme is very different and it lacks vehicles. Also similar are basically any sci-fi RTS games like Red Alert, Total Annihilation, Warzone 2100, etc. Noticable inspirations can be found in Empires Mod, such as the research tech tree and vehicle customization (Warzone 2100).